Loomis's regiment participated in the Battle of Island Number Ten, the Battle of Iuka, the Siege of Corinth, the Siege of Vicksburg, the Battle of Jackson, Mississippi, the Second Battle of Chattanooga and the Battle of Farmington, Tennessee. The "St. Louis Globe Democrat" reported that he acquitted himself well as he rallied his men at the Second Battle of Chattanooga. He led the 26th at the Battle of Missionary Ridge. One memorial tribute described the regiment's effort as a great achievement for a group of citizen soldiers.