Stockton initially showed little interest in politics. He once wrote, "The public is generally unthankful, and I never will become a Servant of it, till I am convinced that by neglecting my own affairs I am doing more acceptable Service to God and Man." Stockton did, however, later take an active role as a trustee of the College of New Jersey.
He served the College, afterwards known as Princeton University, as a trustee. In 1766 and 1767, he gave up his practice for the purpose of visiting England, Scotland, and Ireland. While he was in Scotland, his personal efforts resulted in the acceptance of the presidency of the College by the Reverend John Witherspoon.
Witherspoon's wife had opposed her husbands taking the position but her objections were overcome with the aid of his son-in-law Benjamin Rush, who was a medical student in Edinburgh. This was an exceedingly important event in the history of higher education in America. Stockton returned to America and the following year, 1768, he was made a member of the executive council of the province and in 1774 was promoted to the supreme bench of New Jersey.
Stockton was appointed by Congress, along with fellow signer George Clymer, to an exhausting two-month journey to Fort Ticonderoga, Saratoga and Albany, New York to assist the Continental Army in the American Revolutionary War. On his return to Princeton, he traveled 30 miles east to the home of a friend to evacuate his family to safety, and away from the path of the British army. While there, on November 30, 1776, he was captured in the middle of the night by his own loyalist countrymen and severely beaten. Just before Stockton was captured, General William Howe had offered amnesty to those willing to renounce the American “rebellion” and renew their loyalty to the King George III. Although many took the offer of amnesty, Stockton did not at that time and was marched to Perth Amboy where he was put in irons, and brutally treated as a common criminal.
He was then moved to Provost Prison in New York where he was intentionally starved and subjected to freezing cold weather. After nearly six weeks of brutal treatment, Stockton was released, his health ruined. Over 12,000 prisoners died in the prison ships and prisons in New York compared to 4,435 soldiers that died in combat over the six years of war. His estate, Morven, in Princeton was occupied by General Cornwallis during Stockton's imprisonment; his furniture, all household belongings, crops and livestock were taken or destroyed by the British. His library, one of the finest in the colonies, was burned.
Stockton's treatment in the New York prison prompted Continental Congress to pass a resolution directing George Washington to inquire into the circumstances and not long afterward, Stockton was exchanged on January 3, 1777. The U.S. National Archives contains other messages showing that Washington duly contacted Howe in New York regarding the exchange or release of Stockton and others.
The circumstances of Stockton's release from custody are not entirely clear, but there is evidence that he swore an oath of peaceable obedience to the King. John Witherspoon wrote to his son David in March 1777, stating that Stockton "signed Howe’s Declaration and also gave his Word of Honour that he would not meddle in the least in American affairs during the War". Congressman Abraham Clark, writing to John Hart about filling vacancies in New Jersey's delegation to the Continental Congress, wrote "Mr. Sergeant talks of resigning and Mr. Stockton by his late procedure cannot Act." Fellow signer Dr. Benjamin Rush in his autobiography wrote "At Princeton I met my wife's father who had been plundered of all his household furniture and stock by the British army, and carried a prisoner to New York, from whence he was permitted to return to his family upon parole." (Corner 130) In December of 1777 Stockton again swore an oath of allegiance to the United States.
Stockton's oldest son Richard was an eminent lawyer and later a Senator from New Jersey. His son, Commodore Robert Field Stockton, was a hero of the War of 1812, and in 1846 became the first military governor of California and later a Senator from New Jersey.
In 1969, the New Jersey Legislature passed legislation establishing a state college which was named after Stockton, to honor the memory of New Jersey's signer of the Declaration of Independence. Richard Stockton College of New Jersey is the current name for this educational institution which was previously known under the names Stockton State College and Richard Stockton State College.