The new Manor House of the Patroon was not completed until he was one year old, in 1765, and his father brought him and his mother there so soon as it was ready. His father died October 19, 1769, at the age of twenty-seven, when the son was less than six years old, so the care of the great landed and feudal estate, which had fallen exclusively to him by the rule of primogeniture, was committed to his uncle, General Abraham Ten Broeck. It was managed by him with rare ability throughout the minority of his ward, despite the disturbed condition of affairs during the Revolutionary period, when Albany was the scene of serious preparation for war in collecting men and supplies for the great conflict at Bemis Heights and old Saratoga, or Schuylerville. General Ten Broeck was a participant in this military movement to the north, and was the twenty-eighth mayor of Albany, officiating from April 9, 1779, to June 26, 1783, and a second term from October 15, 1796, to December 31, 1798. He had married Elizabeth Van Rensselaer, daughter of Patroon Stephen Van Rensselaer and Elizabeth Groesbeck, November 1, 1763. Under his direction the Manor House was erected.

Stephen was given his earliest education at Albany by John Waters, who was what was then known as a professional schoolmaster, and, being before the days of printed spelling-books, he was taught from a horn book. A little later, his grandfather, Philip Livingston, took charge of his education, placing him at a school in Elizabethtown, New Jersey; but the troublous times of the Revolution drove Livingston with his family from his home in New York City, and they took refuge in Kingston. Fortunately he established a classical academy there under John Addison, a fine Scotchman possessing thorough scholarship and who was later a state senator. It then became necessary to supply the young man with an advanced education, and he was sent to Princeton, when the celebrated Dr. Witherspoon, scholar, divine and patriot, was president. Witherspoon abandoned education for the pursuit of war, was a Signer of the Declaration, and young Van Rensselaer, to avoid the seat of war, was sent to Cambridge, where he became a Harvard graduate in 1782. In 1825 Yale conferred upon him the degree of Doctor of Laws.

The year following his graduation in 1782, peace had been restored in the United States, and the new nation firmly established. There was no occasion for the young man, then nineteen years of age, to fight. Instead, he turned his attention to matrimony, and married Margaret Schuyler, at "Old" Saratoga (Schuylerville), New York, in 1783. She was third daughter of General Philip Schuyler and Catherine Van Rensselaer. Her next rider sister, Elizabeth, had married Alexander Hamilton, who were thus the uncle and aunt of General Stephen Van Rensselaer. Margaret Schuyler was born in Albany, and baptized there September 24, 1758, and she died there on March 14, 1801. Her remains repose in the center of the Van Rensselaer lot in the Albany Rural Cemetery. Her father was General Philip Schuyler, commander of the Army of the North in 1777, and trusted friend of Washington, who was born in Albany, November 11, 1733, married September 17, 1755, and died in Albany, November 18, 1804. Her mother was Catherine Van Rensselaer, born in The Crailo, Greenbush (Rensselaer, N. Y.), November 4, 1734, died in the Schuyler Mansion, Albany, March 7, 1803, and was daughter of Johannes Van Rensselaer and Engeltie (Angelica) Livingston, the latter being the daughter of Robert Livingston, Jun., twelfth mayor of Albany. John Van Rensselaer became heir of the Claverack patent when his father, Hendrick, died July 2, 1740, and was thus the owner of "The Crailo" in Greenbush, called Rensselaer later. It will be remembered that Hendrick Van Rensselaer was a brother of the last Patroon by the name of Kiliaen — in other words, the younger brother of Stephen's great-grandfather. Hendrick was born in 1667, died in 1689, and had married Catharina Van Brough (or Verbrugge), whose share in the property left by their father, Jeremias, was the Claverack property.

At this time Stephen Van Rensselaer's mother was the wife of Dominie Eilardus Westerlo, whom she had married in Albany, July 19, 1775, and they were residing in the Manor House, which she had a right to do as the Patroon's widow. He was an original Dutchman, born in Groeningen, known widely as a fine scholar, an eminent divine, and as the pastor for a long period of the Dutch Reformed Church in Albany, preaching in the Dutch language for the first fifteen or twenty years of his charge. As Dominie Westerlo, and his wife, the mother of Stephen, were occupying the Manor House, consequently the young man brought his bride to the mansion at the southeast corner of North Market street (Broadway) and North Ferry street, which had served as an ample parsonage. When, however. Stephen reached his majority, Dr. Westerlo and his wife exchanged residences with the young Patroon and his bride, the latter couple leaving the parsonage to occupy the Manor House. The day of his attaining his majority was made one of great celebration, and from miles around the tenantry and the social set of the city flocked to participate in his hospitality.

Mr. Van Rensselaer found it necessary to look critically after the interests of his Manor, for in order to secure good returns it was essential that the lands should be cultivated, and while speculators would buy lands, the farmers, or laborious tillers of the soil, were unwilling to contract for the fee. By offering leases in fee or for long terms at a moderate rental, he readily succeeded in bringing a large proportion of his lands, comprising the greater portion of the counties of Albany and Rensselaer, into cultivation, thus acquiring a goodly income, yet those who knew him have said "he had none of that morbid appetite for wealth which grows ravenous by what it feeds on."

He received his first military commission, as a major of infantry, in 1786, when twenty-two years old, and two years later was promoted to colonel and given command of a regiment. In 1801, Governor John Jay directed the cavalry of New York to be divided from the infantry, and the cavalry formed a single division, with two brigades, and the command of the whole was conferred upon Stephen Van Rensselaer. He bore the commission of major-general of cavalry to his death.

In 1787, he took an important step in his career as a man of character, when twenty-three years of age and on the threshold of a life which might have been one pampered with wanton and luxurious excesses, he deliberately chose, by a formal profession of religious faith and a personal vow of religious obedience, according to the doctrines and discipline of the Christian church as adopted by the Dutch reformers, to pledge himself to a life of temperance, simplicity, truth and purity. How well he kept his vow is known to all who are intimately acquainted with the manner of his life, for his domestic relations were the most tender, and his character before the world harmonious and beautiful, as well as replete with deeds of public service.

Towards the close of 1787, the convention sitting in Philadelphia to frame a constitution, terminated its labors and submitted its work for the judgment of the people. Mr. Van Rensselaer took ground promptly, and was pronouncedly in favor of the constitution. The next spring delegates to the state convention were to be chosen from Albany county, and both Yates and Lansing, who had left the Philadelphia convention before its labors were completed, were residents of the same county and held great power as anti-Federalists. It was to be expected that their views would prevail, yet Mr. Van Rensselaer, urged by his party to uphold their moral force in the controversy, consented to stand as a candidate for the assembly, and despite his popularity was beaten. In the spring of the next year, 1789, however, Mr. Van Rensselaer was again a candidate, and, with the previous question settled, was elected by an enormous majority. In the spring of 1790 he was elected to the state senate, and was re-elected, serving continuously until 1795, as a faithful, vigilant and influential member. On standing committees, of which there were few then, he was always an important member. At the next gubernatorial election, 1795, he was chosen lieutenant-governor, with Hon. John Jay as executive, Messrs. Yates and Floyd heading the opposition ticket. In 1798 both were renominated and elected by handsome majorities. This time Chancellor Livingston was Mr. Jay's opponent, while Mr. Van Rensselaer was the candidate of both Federalists and the antis, so universally popular had he become. At the same time, the plan was to attract votes for Livingston away from Jay. In January, 1801, a convention was held at the Tontine Coffee House in Albany, and Mr. Van Rensselaer was unanimously named the candidate for governor. His nomination was enthusiastically seconded in New York City and at public meetings all over the state. His purity, reliable judgment amd competent acquaintance with interests and business of the state commended him but the parties were at such great odds, the rancor so fearful, that it poisoned even whole families with hatred one for another. DeWitt Clinton was named as his opponent. He was also deservedly popular and a man of great energy in affairs of moment. In the midst of the state campaign announcement of the election of Thomas Jefferson was announced. It helped in large measure to turn the tide, and Mr. Van Rensselaer was defeated by a majority of less than four thousand votes.

In October, 1801, a state convention met at Albany to revise the constitution, and Mr. Van Rensselaer was a member, presiding during much of the deliberations as chairman, although Aaron Burr was its president. In 1807 he was elected to the assembly, with his friend, Abraham Van Vechten, as colleague. In March, 1810, a commission was chosen by the legislature, consisting of seven persons — Gouverneur Morris, DeWitt Clinton and Stephen Van Rensselaer among the more important — for exploring a route for a proposed western canal. In the summer of that year, accompanied by a surveyor, he traveled by horseback inspecting a route for the projected undertaking which resulted in the Erie canal, and they gave their findings in February, 1811. With all his enormous energy he advocated the measure in the assembly, thus giving the plan an impetus very needful because of considerable opposition.

War against Great Britain was declared in June, 1812. This was another crisis in his life. A requisition was made on Governor Tompkins, of New York, and the patriotic governor promptly obeyed, selecting Major General Stephen Van Rensselaer for the command. They were then regarded as rival candidates for the chief magistracy. The line of party were distinctly drawn, and the Federalists were charged with being hostile to the war as being premature and unnecessary. General Van Rensselaer was a Federalist. The appointment placed him in a position of embarrassment, for, should he decline, it would tell against his party, and, on the other hand, he was expected to defend both the northern and western frontier, with no experience in warfare and dealing with decidedly impracticable material in the make-up of fighters. He did not hesitate an instant, but accepted the service. His country had summoned him to the field, and he was ready. He was not a loiterer, for in an incredibly short time he had thrown off the citizen surrounded by political advisers, and had formed his military family. In ten days he arrived at Ogdensburgh, having inspected Sackett's Harbor on the way. On August 13th he was in camp at Lewiston, just one month from his call, and just two months later, on October 13th, he was engaged in one of the most gallant and brilliant affairs of the whole war. He carried his American arms into the enemy's territory, and planted the flag of the United States triumphantly on the Heights of Queenstown. Although gaining a complete victory, unfortunately it was of brief duration, on account of the defection of his troops. Had they remained by him, he could have retained the peninsula of the upper province of Canada for the winter, for it was originally planned that Fort George should also be stormed by regular troops. Very valuable to him had been the services of his aide, Colonel Solomon Van Rensselaer, who was wounded a number of times when in the thickest of the fight. By the shameful refusal of his yeoman soldiery, under the plea of constitutional scruples, to march into the camp which had been won for them, he should have felt wroth; but he reported it as an unvarnished relation of facts, telling the truth plainly, but without complaints or reproaches, for he had done his full duty. The British had lost their General Brock by the engagement, and during the cessation of hostilities agreed upon for six days, both sides proceeded to humanitarian duties of burying the dead and caring for the wounded. General Van Rensselaer informed his antagonist that he should order a salute to be fired at his camp and also at Fort Niagara on the occasion of the funeral solemnities of the brave and lamented Brock, to which the stern General Sheaffe replied: "I feel too strongly the generous tribute which you propose to pay for my departed friend and chief, to be able to express the sense I entertain of it." General Van Rensselaer entered the gubernatorial campaign against Daniel D. Tompkins in the spring of 1813, but his party was in the minority, even though giving him a united support, and he was defeated in the state by 3,600 votes out of the 83,000 cast in the election. In 1816 he was again elected to the assembly, and in March the canal commissioners, with Mr. Van Rensselaer at their head and acting as chairman, presented their report to the legislature, requesting that body to adopt immediate measures for prosecuting the enterprise. In April this great work was authorized, the management committed to a board of canal commissioners, with General Van Rensselaer as a member. He was president of that board for fifteen years, succeeding DeWitt Clinton in April, 1824., and serving until his death in 1839.

In 1819 the legislature was induced to pass an act for the encouragement and improvement of agriculture, appropriating money to be divided ratably among the counties, which were to form county societies, with presidents, who should form a central board. The delegates from twenty-six county societies met at the Capitol in January, 1820, and elected General Van Rensselaer president. In 1819 he was elected regent of the University of the State of New York, and was subsequently the chancellor until his death.

Rev. Timothy Dwight, Travels through New York and New England, 1821

In December, 1823, General Van Rensselaer took his seat in congress for the first time, and was continued in his place by re-election for three successive terms, retiring on March 4, 1829. He held the position of chairman of the committee on agriculture. His report on tariff laws affecting agriculture, made in March, 1824, was a valuable one. His ballot on the presidency, in February, 1825, determined the vote of his state's delegation in favor of Mr. Adams.

On May 5, 1824, the Albany Institute was organized for the purpose of engaging in fields of observation of the natural sciences, for study of new theories and discoveries, and the preparation of learned papers. General Van Rensselaer was elected its first president, having the local prestige of being the president of the Albany Lyceum of Natural History. This society elected him annually through fifteen years, until his death. He perceived the advantage of placing knowledge before the people, and his first movement was to employ Professor Eaton, with several competent assistants, to traverse the state near the route of the Erie canal, taking apparatus and specimens to aid the delivery of lectures before business men and farmers in all the villages along the line. These were given on chemistry, natural philosophy and various branches of natural history, and were given in the summer of 1824 at his expense. The experiment was a success. He had also been accustomed to send his schoolmaster among his tenants in the same capacity, and this led him, on November 5, 1824, to provide a suitable building in Troy, New York, for the conduct of a school under Rev. Dr. Blatchford, to whom he delivered a set of rules for its government. He endowed it with professors, and it was incorporated in 1826 as the Rensselaer Institute. Through the next two years, he paid one-half of its current expenses, and at his death he endowed it. Not alone did he institute the Rensselaer Polytechnic, but to two colleges he gave $5,000 each, and to a single agent for the prosecution of scientific research and advancement of education, no less than $30,000. His benefactions were not only most liberal, but wisely devoted, and in those days these sums were considered fortunes in themselves.

He was connected with the institution of Masonry, having been initiated in 1786, when twenty-two years old, and was placed in official station, becoming successively junior and senior warden, and then master. In 1793 he declined further election in Master's Lodge, but in 1825 was installed in the highest office of Masonry, that of grand master, which act was conducted by Governor DeWitt Clinton.

The funeral of General Van Rensselaer was a most impressive one, perhaps more so than any other at Albany before or afterwards. The religious service was held at the North Dutch Church, and the body, in a simple, unadorned casket, was borne nearly a mile to the family vault, upon men's shoulders, the bearers frequently relieving each other, for no hearse was permitted to receive the hallowed burthen. The mourners, composed of the family, civic officials, Masonic bodies, school societies, the chief magistrate and other executive officers of the state, members of the legislature, all on foot, not a carriage being in use. The military were in citizens' dress; all badges of office were laid aside; no plumes nodded; no helmets glistened; no music murmured — solemn, slow and silent the vast throng moved through the highway to the north.

It is of interest to note the manner in which in those days the intelligence of his death was sent to New York City, where he was well known, and it being necessary to transmit the news because of his prominence in the state's public life. It is recorded in Munsell's "Notes from the Newspapers," as an item of news on that day, January 26, 1839:

"An express was started by Messrs. Baker & Walker, to carry the intelligence of the Patroon's death to New York. A Mr. Dimmick left Albany 14 minutes before 6 p. m. in a sulkey. At Redhook, he found a bridge gone, but mounted his horse and swam the stream, drawing the sulkey after him. At Fishkill, the obstruction was much more formidable. The bridge was gone, and the road for more than half a mile inundated. He again mounted his horse, who pushed gallantly into the flood and swam with his rider and sulkey, over a quarter of a mile, bringing both safely to the opposite shore. Notwithstanding these and other obstructions the express arrived at the Canton House at 20 minutes past 8 o'clock in the morning, having rode over the distance of about 150 miles in 14 h. 31 m."