On July 23, the unit was officially named the 8th Missouri Infantry Regiment. Later that year, it was part of the abortive Confederate defense of Little Rock before retiring to Camp Bragg near Camden. In March 1864, the regiment was sent south into Louisiana to help defend against the Red River campaign. It was then part of a failed attack at the Battle of Pleasant Hill on April 9. After the Union troops involved in the Red River campaign retreated, the 8th Missouri Infantry was sent back to Arkansas, where it pursued a retreating Union column led by Major General Frederick Steele. The regiment was part of a failed attack against Steele on April 30 at the Battle of Jenkins' Ferry. For the remainder of 1864 and the first half of 1865, the unit was stationed at various points in Louisiana and Arkansas. The Confederate Trans-Mississippi Department surrendered on June 2, 1865, and the men of the 8th Missouri Infantry Regiment was paroled on June 7, ending its combat career.