James Wilson was an Episcopalian and a Presbyterian, and a devout Christian.
He was identified as a Episcopalian by the 1995 Information Please Almanac. The Library of Congress and Presbyterian Church, USA were cited as the sources stating he was later a Presbyterian. A Worthy Company: Brief Lives of the Framers of the United States Constitution by M. E. Bradford identified Wilson as a "Deist." (Source: Ian Dorion, "Table of the Religious Affiliations of American Founders", 1997).
From: B. J. Lossing, Signers of the Declaration of Independence, George F. Cooledge & Brother: New York (1848) [reprinted in Lives of the Signers of the Declaration of Independence, WallBuilder Press: Aledo, Texas (1995)], page 129:
For many years, Mr. Wilson stood at the head of the Philadelphia bar, and so popular was he as an advocate, that nearly every important case that came before the higher tribunals of that State was defended by him. As a patriot none was firmer; as a Christian none sincerer; and as a husband, father, neighbor and friend, he was beloved and esteemed in the highest degree.
From: B. J. Lossing, Signers of the Declaration of Independence, George F. Cooledge & Brother: New York (1848) [reprinted in Lives of the Signers of the Declaration of Independence, WallBuilder Press: Aledo, Texas (1995)], page 126-129:
This distinguished patriot was born in Scotland in 1742, and emigrated to this country in 1766. He had received his education under some of the best teachers in Edinburgh, and he brought with him such strong recommendations to eminent citizens of Philadelphia, that he soon obtained a situation as an assistant teacher in the Philadelphia college, then under the supervision of the Reverend Doctor Peters...From: Robert G. Ferris (editor), Signers of the Constitution: Historic Places Commemorating the Signing of the Constitution, published by the United States Department of the Interior, National Park Service: Washington, D.C. (revised edition 1976), pages 221-223:
Having adopted America as his home, Mr. Wilson espoused her cause with all the ardor of a native born citizen. This gave him great popularity, and in 1774, he was elected a member of the Provincial Assembly of Pennsylvania. In May, 1775, he was chosen a delegate to the General Congress, together with Benjamin Franklin and Thomas Willing. He was again elected for the session of 1776,and warmly supported the motion of Richard Henry Lee for absolute independence. He voted for and signed the Declaration of Disenthralment and remained an active member of Congress until 1777, when he and Mr. Clymer were not re-elected in consequence of the operatoins of a strong party spirit which at that time existed in the Pennsylvania Assembly.
Mr. Wilson, however, continued actively engaged for the public good, evenin private life, nor did he allow that jealousy of his rising fame, which had interposed a barrier to his re-election, in the least to repress his zeal for his adopted country's welfare. He had been an indefatigable coadjutor with Mr. Smith int he organization of volunteer military corps, and was elected colonel of a regiment in 1774. The energy he there displayed was now again exerted in raising recruits for the Continental Army, and through his influence, the Pennsylvania line was much strengthened.
In 1777, difficulties having arisen with the Indians within the bounds of the state, Mr. Wilson was sent as a commissioner to treat with them, and he was successful in his undertaking. Soon after the arrival of Mr. Gerard, the French minister, Mr. Wilson formed an acquaintance with him, which ripened into friendship, and Mr. Gerard was so struck with the versatility of his talents, that in 1780 he appointed him the Advocate General of the French nation in the United States, an office which required a thorough knowledge of international and commercial laws. The appointment was confirmed by the French King in 1781.
Toward the close of 1782, Mr. Wilson was again elected a delegate to the General Congress, and took his seat in January, 1783. During that year, the executive council of Pennsylvania, appointed him on agent and counsellor in the controversy of that state with Connecticut, respecting the Wyoming domain. In this important service he was very successful, and the matter was brought to an amicable settlement. He was again elected to Congres toward the close of 1785, and took his seat in March following. He was an active member of the convention that framed the Federal Constitution in 1787, and was chairman of the committee that reported the first draft. He was also a member of the state convention that ratified it, and was chosen to deliver an oration on the occasion of a celebration of the event in Philadelphia. He was also a member of the convention that framed a new constitution for Pennsylvania in 1788. In the arrangement of the judiciary under the Federal Constitution, President Washington appointed Mr. Wilson one of the judges of the Supreme Court of the United States.
He was appointed the first Professor of Law in the College of Philadelphia, in 1790, and when, in 1792, that institution and the University of Pennsylvania were united, he was appointed to the same professorship there, which office, as well as that of Judge of the Supreme Court, he held until his death.
In 1791, the Pennsylvania House of Representatives chose him, by a unanimous vote, to revise and properly digest the laws of the state. He at once entered upon the duties assigned him, and had made a considerable progress in the arduous work, when his labors were arrested by the Senate refusing to concur in the object for which the appointment had been made. His task was never resumed.
In his official capacity as judge of the United States Supreme Circuit Court, he frequently made long journeys into other states. It was while on a judicial circut in North Carolina, that his death occurred on the twenty-eighth day of August, 1798, at the house of his friend, Judge Iredell of Edenton. He was in the fifty-sixth year of his age.
Wilson, who wrote only a few opinions, did not achieve the success on the Supreme Court that his capabilities and experience promised. Indeed, during those years he was the object of much criticism and barely escaped impeachment. For one thing, he tried to influence the enactment of legislation in Pennsylvania favorable to land speculators. Between 1792 and 1795 he also made huge but unwise land investments in western New York and Pennsylvania, as well as in Georgia. This did not stop him from conceiving a grandiose but ill-fated scheme, involving vast sums of European capital, for the recruitment of European colonists and their settlement in the West...
Although first buried at Hayes Plantation near Edenton, his remains were later reinterred in the yard of Christ Church at Philadelphia.