Now commanded by Brig. Gen. William W. Burns, it was then assigned to the Army of the Potomac's II Corps as the 2nd Brigade, 2nd Division. It fought in the Peninsula Campaign, during which the 69th was credited by Maj. Gen. Joseph Hooker with making "the first successful bayonet charge of the war" at the Battle of Glendale. It also fought during the Seven Days battles, including Allen's Farm and Savage Station; at Malvern Hill it was posted on the Union right with the rest of the II Corps and consequently wasn't engaged during the battle.