On May 22, 1861, Carruth, became captain of Company H by election. He first saw combat at First Bull Run in the brigade of Col. Israel B. Richardson. Carruth next served in the Army of the Potomac during the Peninsula Campaign. The regiment was in the III Corps in the division of Maj. Gen. Joseph Hooker. Carruth was present at the Battle of Yorktown (1862), where his company distinguished itself. The company also fought at the Battle of Williamsburg. Carruth was wounded in the arm at the Battle of Seven Pines, apparently missing the subsequent battles of the Peninsula Campaign.