In the spring and early summer of 1862, the regiment participated in Maj. Gen. George B. McClellan's Peninsula Campaign.
Specific engagements included the following: With the end of the unsuccessful campaign, the 7th remained stationary at Harrison's Landing until August 15, when it moved to Fort Monroe.
Although it did not directly participate in the Second Battle of Manassas, the 7th assisted in checking Pope's rout at Bull Run on August 30 and covered the army's retreat to Fairfax Court House on September 1.
Their ranks thinned by the almost continuous campaigning, the 7th Maine was ordered home to recruit fresh troops in October.
It was part of the successful attack on Maryes Heights during the Second Battle of Fredericksburg on May 3 and the fight at Salem Church on May 3–4.
During the autumn, the regiment was involved in the Bristoe Campaign from October 9–22 and the Second Battle of Rappahannock Station on November 7.
After spending the winter stationary in its camp in Virginia, the 7th was part of Ulysses S. Grant's Overland Campaign from the Rapidan River to the James River between May 3-June 15, 1864. it fought in the Battle of the Wilderness May 5–7; Spotsylvania May 8–12 (including attacking the "Bloody Angle" on May 12).
The Maine boys then moved to Washington, D.C., July 9–11 and helped repulse Jubal A.