The infantry in the American Civil War comprised foot-soldiers who fought primarily with small arms and carried the brunt of the fighting on battlefields across the United States. The vast majority of soldiers on both sides of the Civil War fought as infantry and were overwhelmingly volunteers who joined and fought for a variety of reasons. Early in the war, there was great variety in how infantry units were organized and equipped - many copied famous European formations such as the Zouaves - but as time progressed there was more uniformity in their arms and equipment.

The Confederate States Army, also called the Confederate Army or the Southern Army, was the military land force of the Confederate States of America during the American Civil War (1861–1865), fighting against the United States forces to win the independence of the Southern states and uphold and expand the institution of slavery. On February 28, 1861, the Provisional Confederate Congress established a provisional volunteer army and gave control over military operations and authority for mustering state forces and volunteers to the newly chosen Confederate president, Jefferson Davis. Davis was a graduate of the U.S. Military Academy, and colonel of a volunteer regiment during the Mexican–American War. He had also been a United States senator from Mississippi and U.S. Secretary of War under President Franklin Pierce. On March 1, 1861, on behalf of the Confederate government, Davis assumed control of the military situation at Charleston, South Carolina, where South Carolina state militia besieged Fort Sumter in Charleston harbor, held by a small U.S. Army garrison. By March 1861, the Provisional Confederate Congress expanded the provisional forces and established a more permanent Confederate States Army.