The 2nd New Jersey Infantry Regiment was first organized at Trenton, New Jersey for three months service on April 26, 1861 and mustered in May 1, 1861 under the command of Colonel George W. McLean.

The regiment was attached to Runyon's New Jersey Brigade, Defenses of Washington, to June 1861.

1st Brigade, Runyon's Reserve Division, McDowell's Army of Northeast Virginia, to July 1861.

Reported to General Butler at Annapolis, Maryland, May 5, then moved to Washington, arriving there May 6.

Duty on line of Alexandria & Loudon Railroad until July 16.

The 2nd New Jersey Infantry mustered out of service July 21, 1861 at Trenton.

[1] The 2nd New Jersey Infantry was reorganized at Camp Olden in Trenton for three years service on May 27, 1861 under the command of Colonel Samuel L. Buck.

The regiment was attached to 2nd Brigade, Runyon's Reserve Division, McDowell's Army of Northeast Virginia, to August 1861.

Kearney's Brigade, Franklin's Division, Army of the Potomac, to March 1862.

1st Brigade, 1st Division, I Corps, Army of the Potomac, to April 1862.

Charles City Cross Roads and Glendale June 30.

At Harrison's Landing until August 16, Movement to Fort Monroe and Manassas, Va., June 16–26.

Pope's Campaign in northern Virginia August 26 – September 2.

Action at Bull Run Bridge, Manassas, August 27.

Pursuit of Lee to Manassas Gap, Va. Fairfield, Pa., July 5.

Repulse of Early's attack on Fort Stevens and the northern defenses of Washington July 11–12.

Sheridan's Shenandoah Valley Campaign August 7 – November 28.

Veterans and recruits were temporarily attached to the 15th New Jersey Volunteer Infantry under orders of May 29, 1864, until December 17, 1864, when the regiment was reorganized as a battalion.

Non-veterans mustered out at Newark, New Jersey on June 21, 1864.

The 2nd New Jersey Infantry mustered out of service July 11, 1865 at Hall's Hill, Virginia.