[3] In the Summer of 1814, after Trousdale had been at home for just a few months, he joined a militia company formed by Lieutenant-Colonel George Elliott.

[3] Following the capture of Pensacola, Trousdale's unit hurried westward with Jackson's forces to defend New Orleans from an impending British invasion.

[1] At the outbreak of the Second Seminole War in 1836, Trousdale formed his own company, and was elected colonel of the Second Regiment, First Brigade.

[3] His regiment took part in several skirmishes, and helped defeat Seminole forces at the Battle of Wahoo Swamp in November 1836.

[1] In 1837, Trousdale once again ran for Congress for the 6th District congressional seat, but lost to William B. Campbell, his former subordinate in the Seminole War and his future gubernatorial opponent.

[3] For his actions at Chapultepec, Trousdale was brevetted to brigadier general by President James K. Polk on August 23, 1848.

At the Nashville Convention in 1850, which Trousdale had endorsed, southern Democrats called for secession should the United States implement the Wilmot Proviso, banning slavery in territory acquired as a result of the Mexican–American War.

Secession was unpopular in Tennessee at the time, and following a relatively dignified campaign, Campbell defeated Trousdale by 1,500 votes.

He was consistently stricken with rheumatism, creating physical difficulties that prevented him from taking part in public life, as well as from serving in the Civil War in the 1860s.

He nevertheless supported the Confederacy, and refused to take the Oath of Allegiance to the United States, even when Union soldiers occupied his home.

[6] His family home, the Federal-style "Trousdale Place" located near the town square of Gallatin, has been a preserved historical site since 1900.