On May 2, 1777, he was appointed colonel of the First State Regiment of Foot, and on July 16 was commissioned Adjutant-General of Pennsylvania.
In October of this year his barns, barracks, grain, and hay were burned by the British, and his wagons, horses, cattle, sheep and Negroes carried off, although General Howe had given his word to Mrs. Bull that they would not be disturbed.
In December, when General James Irvine was captured, General Bull succeeded to the command of the Second Brigade of Pennsylvania militia, under General John Armstrong.
While the British were in possession of Philadelphia a brigade of Continental troops under Colonel John Bull on the evening of December 24, 1777, made an excursion into Fourth Street in Philadelphia, with two thousand militia, and three pieces of cannon, and alarmed the city by firing off the heavy guns, whereby some of the balls fell about old Christ Church. Colonel Bull then made a good retreat back to his station, without the loss of a man.
During 1778 and 1779 he was engaged in erecting defenses for Philadelphia and in latter year he put down the chevaux de frize in the Delaware to obstruct the approach of British ships. In 1780 he served as Commissary of Purchase at Philadelphia, and appears to have been one of the busiest and most indefatigable of workers.
In the year 1785 he removed to Northumberland, being attracted there by the location of the town and the belief that it would become a large place.
In 1802 he was a candidate for the Legislature but was defeated by Simon Snyder, afterwards Governor of the State. In 1805 General Bull was elected to the General Assembly, but in 1808 he was defeated for Congress when he ran as the Federalist candidate.
Mrs. Mary Bull, his wife, died February 23, 1811, aged eighty years. The Northumberland Argus says, “She was buried in the Quaker graveyard, and General Bull, though much reduced by sickness and old age, previous to the grave being closed, addressed the people as follows: 'The Lord gave and the Lord hath taken away, blessed be the name of the Lord; may we who are soon to follow be as well prepared as she was.'”
General Bull died August 9, 1824, in the 94th year of his age.
This distinguished patriot and citizen lies buried beside his wife in the Riverside Cemetery, Northumberland, where a monument should be erected in memory of this distinguished, yet eccentric, officer of the French and Indian and Revolutionary Wars.