[5] In July and August, 1863 Peck saw action at Yorktown and Gloucester Court House, and he was involved in combat at Young's Crossroads (now Maysville), North Carolina in December, 1863.

[3] In late 1864 and early 1865 Peck assumed temporary command of a battalion in the 9th Vermont, and was then appointed acting regimental quartermaster and adjutant.

The left of the Union line lay near the river, while the right was in the woods and was commanded by 1st Lieutenant T. S. Peck, Company H, 9th Vermont Volunteers.

Lieutenant Peck had made a desperate fight all the afternoon, and had been the farthest out toward the enemy the entire time, holding them in check until they had broken through the line on his left.

This order was instantly obeyed, although some were killed and wounded in leaving the enemy, who came forward on the run, increasing their musketry fire.

The Confederates brought up a battery and poured in grape and canister, but the rear guard of the 9th stood to the bridge until it was destroyed and the enemy prevented from crossing.

The river at this point, although narrow, was very deep, and the enemy was obliged to construct a bridge before crossing the stream, which gave the Union men an advantage of about three hours, and saved the command.

Citation: By long and persistent resistance and burning the bridges, kept a superior force of the enemy at bay and covered the retreat of the garrison.

[11] Peck was an active member of the Grand Army of the Republic, the Military Order of the Loyal Legion of the United States, and the Reunion Society of Vermont Officers.

[21] Peck joined the Vermont National Guard after the Civil War and served in various command and staff positions, attaining the rank of lieutenant colonel.

Theodore S. Peck married Agnes Louise Lesslie (July 29, 1843 – November 15, 1917) of Toronto, Ontario, Canada on October 29, 1879.

Her works included the 1900 poem A Dream of the Flag and three novels; 1907's Hester of the Grants: A Romance of Old Bennington; 1908's The Sword of Dundee: A Tale of Bonnie Prince Charlie; and 1914's White Dawn: A Legend of Ticonderoga.