 He served in the Revolutionary War as lieutenant colonel of militia in 1782 and later as general of militia in Virginia.Trigg was a delegate to the Virginia ratification convention of 1788, and voted with Patrick Henry and the Anti-federalists against ratification of the United States Constitution.He was elected as a Republican to the Fifth and to the five succeeding Congresses (March 4, 1797 – March 3, 1809).