Parsons was murdered by Captain Dario Garza, at the head of a body of Mexican soldiers, on or about August 15, 1865, near China, Nuevo León, Mexico.

He served as a volunteer in the Mexican–American War with the rank of captain in Colonel Alexander W. Doniphan's regiment and was cited for gallantry at the Battle of Sacramento on February 28, 1847.

Parsons was commissioned a brigadier general of the Confederacy on November 5, 1862, and led his infantry brigade in the Battle of Prairie Grove, Arkansas, one month later.

His force would participate in the attack at Helena, Arkansas on July 4, 1863, and assisted Richard Taylor in thwarting Union Major General Nathaniel Banks' Red River Campaign of 1864 in Louisiana (Battle of Pleasant Hill), as well as opposing Union Major General Frederick Steele's Camden Expedition in Arkansas, including participation at the Battle of Jenkins' Ferry.

Parsons was appointed a major general by Trans-Mississippi Departmental Commander Kirby Smith on April 30, 1864, although his promotion was never confirmed by Jefferson Davis.