Mustered into service as a Private on July 29th, 1861
Private O'Rourke was discharged from the 19th Indiana for disability on April 18th, 1862. After returning to Indiana he recovered from his sickness and joined Company K of the 16th Indiana Infantry on August 19th, 1862. At the Battle of Richmond Kentucky in late August of 1862 Michael was wounded in the right foot that required amputation. He was discharged from the service for disability on March 3rd, 1863.
He would file for a pension on March 16th, 1863.
Currently his date of death and place of burial is unknown.