He commanded the 3rd Brigade, 3rd Division, II Corps, after Col. George L. Willard's death on July 2, 1863, at the Battle of Gettysburg. Sherrill, in his first full day commanding the brigade, was positioned near Ziegler's Grove on Cemetery Ridge, when he was mortally wounded on July 3 by a musket shot in the bowels. Carried off the field by men of the 39th New York Infantry, he was taken to the XI Corps field hospital, where he died about 8:00 a.m. the next day. His body was sent by the regimental surgeon to Baltimore for embalming. Lt. Col. James M. Bull, 126th New York Infantry, who filed the brigade's report, giving a detailed account of the artillery barrage on July 3 but not much on the repulse of Pickett's Charge, places Sherrill's death at 4 p.m.