It was one of the 18 Massachusetts regiments formed in response to President Abraham Lincoln's August 1862 call for 300,000 men to serve for nine months.

The regiment was recruited in Essex County and rendezvoused for mustering in at Camp Edwin M. Stanton in Boxford, Massachusetts.

The 50th Massachusetts was assigned to the Department of the Gulf under Major General Nathaniel P. Banks and shipped for Louisiana.

[2] On November 19, the regiment departed Massachusetts by rail to Norwich, Connecticut and then took steamships to New York City.

Due to various delays, being held for some time at Hilton Head, South Carolina, three more companies arrived at Baton Rough on February 1, 1863.

On March 20, the regiment was posted at Winters Plantation, across the Mississippi River from Confederate-held Port Hudson and conducted picket duty there for a week, then returned to Baton Rouge.

[3] The 50th Massachusetts left camp with its brigade on May 12, 1863 about a week before the main body of Banks's forces to serve guard duty near an important crossing of White's Bayou.

During this assault, the 50th Massachusetts supported Union batteries and did not take part in the unsuccessful advance on the Confederate fortifications.