This fish is best described as a deep bodied, silvery fish whose head and body slope steeply up from the snout to the dorsal fin, resulting in a hump-backed appearance. It has a long dorsal fin that is divided into two lobes. The first has 8 to 9 spines, and the second has a single spine with 24 to 32 soft rays. The anal fin has 2 spines with the second spine larger than the first. The pelvic fin has one spine with 5 rays.
Ctenoid scales cover the body and upper head.
The lateral line is complete and extends through the caudal fin. The back is gray, with the sides silvery and belly and lower region of the head white. Adults commonly weigh up to 5 pounds, but the current Iowa record was a 46-pound fish caught in Spirit Lake in 1962. The drum spends most of its time on or near the bottom feeding mainly on fish, crayfish, and immature insects. Moving slowly along the bottom, it moves small rocks and other bottom materials with its snout, capturing displaced aquatic life.