[2] A Whig, he ran for the United States House of Representatives in 1855, but was defeated by the Democratic incumbent, Fayette McMullen.

[3] Trigg largely avoided Knoxville politics until the secession crisis intensified in the weeks following the election of President Abraham Lincoln.

[3] In May and June 1861, he was one of Knox's delegates to the Unionist East Tennessee Convention.

[3] He served as chairman of the convention's business committee, which was tasked with drafting a set of grievances and resolutions.

[1] He was confirmed by the United States Senate on July 17, 1862, and received his commission the same day.