In July 1861over 1,000 men from Erie and other counties volunteered for 3 year service. The new regiment was mustered into US Army service on 8 September 1861 with Colonel McLane and Strong Vincent as its Major. The regiment was assigned to Gen. Fitz John Porter's division which later became the Fifth Corps of the Army of the Potomac.
The 83rd Pennsylvania was one of three regiments to be awarded French chasseur uniforms. The uniforms were awarded to units that excelled in drill and in appearance during dress parade. They were trained as a chasseur, or light infantry unit. The chasseur outfits came complete with everything from jackets and boots to tents and clothing brushes.
The regiment's first action was at Hanover Court House on 27 May 1862. During the Seven Days Battles, summer 1862, they suffered the fourth highest losses in the entire Federal army. At the battle of Fredericksburg, the 83rd along with the rest of the 5th Corps, fought against the rebel army at Marye's Heights, but took huge casualties.
In early May, 1863 they fought at Chancellorsville, it was here that General Stonewall Jackson was killed. At the Battle of Gettysburg in July 1863, Colonel Vincent led the brigade in the defense of Little Round Top.
The 83rd also took part in the all major engagements of Grant's 1864 campaign beginning with the Battle of the Wilderness, North Anna River, Cold Harbor, Petersburg, Weldon Railroad, Poplar Springs and Hatcher's Run (Dabney's Mill).
The brigade received the formal surrender of Lee's army on the 21st of April 1865. They were mustered out of service on 28 June 1865.
A total of 1,794 men served in the 83d Pennsylvania Volunteer Infantry during the Civil War. 311 men were killed or died while in service and another 397 were discharged due to wounds or sickness.