When the Civil War broke out in 1861, he was commissioned Colonel in the 3rd Illinois Infantry, which he had organized. He took the regiment to Missouri where it saw service in a number of minor actions during the winter. He was appointed a Brigadier General in 1862, but his nomination remained unconfirmed by the Senate until it expired. In the interim, he took part in the capture of Arkansas Post in January 1863Ø¢eing wounded in the arm but continuing to command his brigade. He resigned from service in March 1863.
