On October 4, the 2nd Missouri Infantry, along with the rest of Colonel Elijah Gates' brigade, captured a fortification known as Battery Powell, but were forced to retreat by Union reinforcements.

[3] In the early stages of the battle, the 2nd Missouri Infantry was deployed in a ravine when Major General Sterling Price's Confederate division, of which Little's brigade was a part, encountered Union forces along the approach to a local landmark named Elkhorn Tavern.

The charge eventually broke the Union line, and the 2nd Missouri Infantry helped capture a portion of the 3rd Iowa Battery, despite taking heavy casualties from canister fire.

[6] Union troops then pressed a counterattack, forcing the 2nd Missouri Infantry, as well as the rest of Price's division, to retreat.

A muster conducted in Corinth in early May found 923 men officially listed on the regiment's rolls, but only 590 of them were reported as present for duty.

The Confederate charge hit the division of Brigadier General Thomas A. Davies, breaking the Union line.

[15] However, reinforcements were not sent to follow up the breakthrough, and a Union counterattack drove the 2nd Missouri Infantry and the rest of Gates' brigade from the ground they had won.

[18] Later in the afternoon, Cockrell's brigade responded with a counterattack, driving Union troops back and recapturing the cannons of Waddell's Alabama Battery, which had been captured earlier in the fighting.

The attackers suffered heavy casualties in the charge, one member of Cockrell's brigade later wrote that "blood ran in a stream, as water would have done.

"[19] The charge gained momentum, eventually reaching the top of Champion Hill, a prominent landmark on the battlefield.

[21] At Champion Hill, the 2nd Missouri Infantry suffered casualties of 10 men killed, 35 wounded, and 38 missing, for a total of 83.

[11] On May 17, the 2nd Missouri Infantry was part of a rear guard holding the crossing of the Big Black River in Mississippi.

A Union attack broke through the Confederate line, forcing the 2nd Missouri Infantry and the rest of Cockrell's brigade to break for the rear.

During the Siege of Vicksburg, elements of the brigade were initially held as a reserve, but were eventually sent to various weak points in the line.

On May 19, Union troops made a determined assault against the Confederate lines, and the 2nd Missouri Infantry was sent to a position known as the 27th Louisiana Lunette.

[24] Later that day, a small group from the regiment burned a house lying between the lines to prevent Union troops from using it as cover.

[26] The routine siege action also took a toll on the regiment; two men of the 2nd Missouri were killed by Union shellfire on June 26.

The regiment's lieutenant colonels were Hull, who resigned on May 8, 1862; Cockrell; Dwyer, who died on March 21, 1863; Senteny, and Thomas M. Carter.