It began as a Confederate Army unit in 1861, and surrendered to the Union at the Battle of Appomattox Court House in 1865.

In world War II it served as a guard battalion in Europe, for which it added a lion to its coat of arms to symbolize its service in northern France.

They were reorganized in part on 26 December 1891 as the 1st and 2nd Battalions of Infantry and transferred to the Louisiana State National Guard.

The battalions consolidated on 17 March 1896 to form the 1st Regiment of Infantry with headquarters at Baton Rouge.

It was reorganized on 8 August 1899 in the Louisiana State National Guard as the 1st Battalion of Infantry with headquarters at Monroe.

The 156th Infantry arrived at the port of Newport News, Virginia, on 31 December 1918 on the USS Princess Matoika, and was demobilized on 23 January 1919 at Camp Beauregard, Louisiana.

The 156th Infantry was inducted into active federal service at New Orleans on 20 November 1940, and moved to Camp Blanding, Florida, where it arrived on 21 December 1940.

The 156th went ashore in France in June 1944 and acted as a separate infantry regiment, performing guard duties at headquarters, POW camps (like CCPWE26 in Belgium) or supply installations, and containing German troops bypassed by allied forces in France.

The regiment returned to the United States and was inactivated on 13 March 1946 at Camp Kilmer, New Jersey.

[4] A Silver color metal and enamel device 1 1/8 inches (2.86 cm) in height overall consisting of a shield blazoned: Per fess enhanced Azure and Argent in chief a saltire couped of the second and in base a leopard passant guardant of the first armed and langued Gules.

Attached below and to the sides of the shield a Blue scroll inscribed "DIEU ET MOI" in Silver letters.

The organization's honorable Civil War service is shown by the saltire, (St. Andrews cross), taken from the Confederate battle flag.