From this source:
Dr. Hitchcock proved himself a man of talent, sociable, friendly, hospitable, though somewhat eccentric, and very witty. "Be merry and wise" was his advice to the young on occasions of joy. In belief he was a high Arian and liberal. His funeral services consisted of only a prayer, by his request. His pastorate extended over a period of fifty-five years. He died Aug. 8, 18o3, after an indisposition of four years, when the parish honored his memory by the following vote: "That the parish procure a pair of Tombstones for the Rev. Gad Hitchcock."
And from this source:
During the Revolutionary War, he was a warm friend to the American cause, and, in several instances, officiated as Chaplain. On these occasions, he not only attended diligently to the appropriate duties of his office, but proved to the soldiers that he was not disposed to screen himself from the dangers that he encouraged them to encounter. At a subsequent period, he was a member of the Convention that framed the Constitution of Massachusetts.
In 1787 he was honoured with the degree of Doctor of Divinity from Harvard College....
As to his religious opinions, I suppose there is no doubt that, through his whole ministry, he was a High Arian, and a constant preacher of the doctrines in that age termed liberal; but, if now living, probably he would be standing midway between what is called Orthodoxy and Modern Liberality.
And finally one of his notable patriotic sermons.