[1] When the American Civil War began, Cameron was a doctor in practice at Valparaiso and a member of the Indiana House of Representatives.

[5] After those three months were up, Cameron re-enlisted for the duration of hostilities[1] and was appointed lieutenant colonel of the 19th Indiana Infantry on July 29.

[6] In September 1861, Cameron and the 19th Indiana fought in a skirmish at Chain Bridge, one of the bridges over the Potomac River leading into Washington, D.C. After the action Col. Solomon Meredith, Cameron's brigade commander, thought highly of his performance, stating that he "rode the lines giving orders and maintaining a calmness that was not even shattered when the concussion of a shell brought his horse to its knees."

Despite this praise, Cameron was not able to get along with Meredith, and asked Indiana governor Oliver Morton to be removed from the 19th and assigned elsewhere.

[6] With his regiment Cameron participated in the 1863 Vicksburg Campaign, where he was slightly wounded in his eyes during the Battle of Port Gibson on May 1.

After several stints of brigade command in late 1863 and 1864,[9] he led a division of the XIII Corps during the 1864 Red River Campaign.

[3] Cameron then moved to San Francisco, California, where he stayed there for few years before returning to Colorado to serve as a postal clerk in Denver.