Paterson completed his studies within a year and was admitted to the bar; in 1769 he became an attorney of the Supreme Court of New Jersey. In the same year he opened a general store and began the practice of the law in New Bromley, Hunterdon county, a settlement about thirty miles from Princeton. What inducements persuaded him to select New Bromley as a field for his activities his letters do not disclose, but that he had some misgivings as to the immediate future is apparent from a letter he wrote on May 20, 1769:
"I am in daily expectation of bidding adieu to Princeton and removing far back into the country, where I shall live mewed up, conversing with none but the dead."
That his venture into the less civilized part of New Jersey did not meet with his expectations is apparent from the following letter written to John Macpherson, with whom he was on terms of intimate friendship:
"The truth is I am living in a part of the province destitute almost wholly of conversable beings. Ah, Jack, would to heaven you could toss me a few of your city fools, for, although we have dunces enough in the country, yet they are far from being so merry as those of the town."
He soon found that his income from the store and the practice of the law was not sufficient to meet his wants nor to satisfy his ambition for a more active life. In 1772 he returned to Princeton but remained there a very short time and then removed to Raritan in Somerset County, where he became the junior partner in the firm of Thomas Paterson & Company, the senior partner being his younger brother. This partnership continued until 1779, William dividing his time between his duties as storekeeper and legal adviser.
In the meantime he had been elected to the legislative council and appointed Attorney-General of the state, an office he held for a number of years. At Paterson Farm, as he had named his estate, he had a little office building adjoining his dwelling. There were always law students in this little office and among them in 1779 was Aaron Burr. Numerous letters from Burr to Paterson and from Paterson to Burr attest the growing intimacy which existed between these two prominent figures in the early days of the republic. Burr studied law in Paterson's office for six months, leaving there in
During these days and those following the out break of hostilities with the mother country Paterson was a busy man. His travels from place to place wherever his duties called him were generally on horseback.
Upon the return of peace he removed to New Brunswick, where he had so often attended court, retaining his residence there for the rest of his life. That he was busy at the bar is attested by the records which show that at one term of the county courts he appeared as counsel in seventy-five cases.
That Paterson took a very active part in the formation of the state constitution ("Charter" it was called until by legislative enactment the title was changed to Constitution) is admitted; how extensive this active part was is a moot question. As in the days when horseflesh was more abundant than it is at present many a well-matched team was made up of one animal ready to do all the pulling, its mate being perfectly satisfied with the arrangement, Paterson was always the pulling horse, ever greedy for work, not caring to whom credit was given, provided the allotted task had been decently accomplished. It may consequently be admitted that Paterson's energies were exerted to their full extent by the duties imposed. Cortlandt Parker, in an address delivered at Princeton in 1899, declared that on Paterson devolved most of the work of compiling. Jonathan D. Sergeant and Dr. John Witherspoon were also active. In fact, Charles D. Erdman in his "New Jersey Constitution of 1776" asserts that the work was chiefly done by Sergeant. That the task was satisfactorily accomplished is witnessed by the fact that the New Jersey constitution lasted longer than the constitution of any other state in the Union. It was nearly seventy years before the ever increasing population of the state indicated any amendment.
Paterson's work of greatest utility to the state, especially to the legal fraternity, was begun when he was chief executive of the state, but it was not completed until some years afterwards. The laws of the state and the procedure in the courts were in a badly complicated state; the old common law of England furnished the basis both for legal enactments and procedure, but numerous questions arose when it was made apparent that neither was suitable to the conditions in the state brought about by the revolution. The work of straightening out the complexities was begun by Governor Paterson with making a codification of the rules of practice of common law and of Chancery; the codification was published under the title of "Paterson's Practice Laws."
It was in 1792 that the legislature enacted a law providing that the governor should be appointed and authorized to collect and reduce to proper form under certain heads or titles "all the statutes of England or Great Britain, which before the revolution were practiced and which by the constitution extend to this state;" he was also authorized to codify all the public acts passed by the legislature of the state since the revolution. The act also provided that the work upon completion should be laid before the legislature to be enacted into law.
Of the task thus laid upon the shoulders of the governor by the legislature, Judge Elmer says:
"This important work was entered upon, departing, however, from the plan at first proposed, probably as well because the duties as judge soon interrupted his labors, and because it was more convenient to the legislature to act upon the newly prepared statutes from time to time, rather than to undertake such a work at one sitting. He continued to revise, and, as far as necessary, to remodel the British statutes proper to be re-enacted, during the succeeding five or six years, and that were from time to time adopted by the legislature as a part of the statute law of the state. In 1795 it was enacted that he be authorized, according to his discretion, to correct, and modify such of the statutes which he had not reported upon and he was requested to translate the Latin and French terms as near as may be into English. It appears that he had ceased to report any new laws after 1798. In that year he was allowed six hundred pounds for the printing of the laws prepared by him. Upon the completion of the revision of the British statutes an act was passed which enacted that hereafter no statute or act of Parliament of England or Great Britain shall have force or authority within this state, or be considered a law thereof. The legislature added another section, of which Paterson is not supposed to have approved, to the effect that no judication, decision or opinion, given in any court of law or equity in Great Britain, or in any cause therein depending, nor any printed or written report, or statement thereof, or any compilation, commentary, digest, lecture, treatise, or any such work, or any explanation, or exposition of the common law, made, had, given or composed since the fourth day of July, 1776, in Great Britain, shall be received or read in any court of law or equity of this state, or evidence of the law, or elucidation or explanation thereof, any practice, opinion or sentiment of the said courts of justice, used, entertained or expressed to the contrary thereof notwithstanding. In the next year it was somewhat modified, but in 1801 it was re-enacted and it remained a part of the laws of this state until 1818 when it was repealed."
When the work was completed Paterson received $2500 for his services. Two editions of the compilation were published, one in large folio and the other in large octavo. In 1799 the work was completed.
Of his work and appearance in court Judge Elmer says:
"Judge Paterson, though possessing an intellect and ability of high order, was not an orator in the ordinary acceptation of the term. He was a diligent and laborious student and as a lawyer he prepared his cases with much examination. Indeed, it is understood that he seldom addressed a court or jury without copious notes and often from a written argument, a practice, however, by no means peculiar to him. He himself states in a letter to President Lawrence that he 'was not one of those ready men, who can at the bar take up a long and intricate cause and manage it with ease and address.' He evidently distrusted his own ability, though it is certain that industry and application, however persevering of themselves, could never obtain the reputation of eminence he obtained in after life."
For many years students of New Jersey history sought in vain to find a portrait of William Paterson. William Nelson, for many years secretary of the New Jersey Historical Society, finally found an oil-covered portrait by Sharles, in the possession of J. Lawrence Boggs. He had a copy made, his object being to send it to the gallery of the historical society. Then he had a plate made of the portrait and this has served in numerous publications since then.