[1] In October 1857, Elliot attended the University of Michigan at the Phi Alpha Literary Society courses before graduating in June 1861.

[2][3][4] On September 2, 1861, Elliott entered service as a captain of the 33rd Illinois Infantry Regiment but was wounded and captured on October 15, 1861, but was exchanged in May 1862.

[5] After being promoted to Lieutenant Colonel on September 13, 1864, Elliott was brevetted Brigadier general on March 13, 1865, for his services at the battles of Port Gibson, Champion Hill, Big Black River Bridge, Vicksburg and Spanish Fort.

[2][4] From 1880 to 1884, Elliott re-enlisted in the United States Army as the Adjutant general of Illinois and became a member of the Loyal Legion around this time.

[2][4] Elliott died on December 3, 1922, at White Plains, New York and was buried at Mount Pleasant Cemetery.