During its service with the X Corps, the 54th Massachusetts took part in operations against Charleston, South Carolina, including the Battle of Grimball's Landing on July 16, 1863, and the more famous Second Battle of Fort Wagner on July 18, 1863. During the latter engagement, the 54th Massachusetts, with other Union regiments, executed a frontal assault against Fort Wagner and suffered casualties of 20 killed, 125 wounded, and 102 missing (primarily presumed dead)—roughly 40 percent of the unit's numbers at that time. Col. Robert G. Shaw was killed on the parapet of Fort Wagner. In 1864, as part of the Union Army's Department of Florida, the 54th Massachusetts took part in the Battle of Olustee.