Ozark was originally designed to be the lead ship in a class of riverine monitors armed with traditional turrets and a new, experimental underwater battery, essentially a 9" Dahlgren firing through a pipe exiting beneath the waterline. While theoretically plausible, the massive cost overrruns of the project caused it to be abruptly cancelled, delaying Ozark's completion by a year and cancelling the contracts for construction of her sister ships. She entered service in January of 1864 and spent her entire time in commission as part of the Mississippi River Squadron. She was involved in number of operations, including the attack on Alexandria, Louisiana and the ultimately failed Red River Campaign. She remained on Mississippi station following in the end of the war, and was briefly purchased for private use before again entering military service as a guard ship. In 1873, she was involved in the transportation and protection of witnesses to the Colfax Massacre, in which several African-Americans were murdered by whites, an act her former commanding officer called a "noble act befitting her."
Ozark was quite an unusual monitor. In addition to the provisions for the never installed underwater gun, she featured three, tall rudders which appeared like a fishtail and were visible above the waterline, and two large deck structures: a large centrally located "deck house" and a smaller "machine house" sitting directly over the machinery controlling her rudders.