Sent from New Orleans to defend against the Federal descent of the Mississippi, she was among the force that engaged vessels of the Union Army's Western Gunboat Flotilla at the Battle of Plum Point Bend on May 10, 1862.

On January 25, 1862, Montgomery began her conversion to a cotton-clad ram by placing a 4-inch oak sheath with a 1-inch iron covering on her bow, and by installing double pine bulkheads filled with compressed cotton bales to protect her engines.

[1] On April 11, Little Rebel's conversion was completed and she steamed from New Orleans to Fort Pillow, Tennessee, where she operated in defense of the river approaches to Memphis.

Brigadier General M. Jeff Thompson, CSA, who witnessed the battle said that Little Rebel, under a shower of enemy missiles, "ran amid the storm as heedlessly as if charmed.

Following the Federal capture of Fort Pillow, Flag Officer Charles Henry Davis, USN, commanding the Western Flotilla, pressed on without delay and appeared off Memphis with a superior force on June 6, 1862.

The Confederate vessel was hit in her boilers by fire from USS Carondelet and then was struck by Monarch and driven ashore by the blow.

The Ships log was kept during union service by Acting Assistant Engineer Albert martin Clinton Smith (1834–67), a native of New Haven, Oswego County New York.