Wounded on 7 April 1862 at the Battle of Shiloh. Ferris first enlisted as a Private in Company I, 1st Wisconsin Infantry. He then entered the 14th Wisconsin Infantry. On 18 April 1862 he was commissioned 1st Lieutenant of Company A, 14th Wisconsin Infantry. This promotion was less than 2 weeks after the Battle of Shiloh, the promotion no doubt in order to fill the gaps in the rank structure caused by casualties at Shiloh.
He would eventually become Lieutenant Colonel of the 14th Wisconsin Infantry and would muster out on 9 October 1865 in Mobile, Alabama.