During the American Civil War, he won distinction for his service in the Mississippi Squadron at the Battle of Fort Henry on 6 February 1862; and at Pittsburgh Landing on 1 March 1862; and again on 6 and 7 April 1862. During the latter engagement at Pittsburgh Landing, his ship, , in company with , prevented the Confederate forces from crossing the river and saved the Union Army from defeat in the Battle of Shiloh. He later took part in engagements with Confederate batteries at Chickasaw Bayou, St. Charles, White River, Arkansas Post and the passage of the Vicksburg batteries. During the siege of Vicksburg, his ship, , was frequently under fire between 19 May and the Confederate surrender on 4 July 1863.