Then he served as chief of staff to Maj. Ambrose Burnside during the battles of Antietam and Fredericksburg. He assumed command of the IX Corps and was sent to the Western Theater for the Vicksburg Campaign. Parke then was Burnside's chief of staff in the Army of the Ohio in the defense of Knoxville.
Parke served as chief of staff to Burnside during the Overland Campaign, in which the latter commanded IX Corps, as well as in the beginning stages of the Siege of Petersburg. After the Battle of the Crater, Burnside was relieved of command and Parke assumed command of the IX Corps. He led it at the Battle of Globe Tavern, the Battle of Peebles' Farm, and the Battle of Boydton Plank Road. In 1865, while Army of the Potomac commander Maj.
He led the IX Corps through the fall of Petersburg and the Appomattox Campaign. In 1865 he was appointed brevet major general in the regular army in recognition of his service at Fort Stedman.