The 33rd Illinois took part in the Jackson Expedition, which involved continuous fighting during 9–16 July 1863. While skirmishing on 13 July, Private Joseph W. Fifer from the regiment was wounded. Fifer would later become governor of Illinois. The Confederate defenders evacuated Jackson, Mississippi, a few days later. The 33rd Illinois was part of 1st Brigade, 1st Division, XIII Corps in July–August 1863. The unit had garrison duty at Vicksburg until August 20 when it was transferred to the Department of the Gulf, where it served until June 1864. The regiment garrisoned New Orleans, Brashear City, and Berwick, Louisiana, until October 1863. The unit participated in the Western Louisiana Campaign on 3 October–10 November. For the 33rd Illinois, this operation up the Bayou Teche was a lark in which the soldiers stole "wagonloads" of chickens from the inhabitants. While marching through New Iberia the men of the regiment began howling. The men claimed that this scared the townspeople so badly that they began to fly French flags from their homes. The regiment served with Union troops from eastern states. According to one 33rd Illinois soldier, the easterners, "wore more feathers and less dust than those from the West." When soldiers of the 33rd Illinois and the 3rd Rhode Island Cavalry Regiment got into a drunken fistfight, the Illinoisans ended with fewer injuries.