Benwolf's appearance is based on a classic werewolf. He has grey fur and a long flowing mane and large bushy tail, with three sharp claws on each hand. The inside of his mouth is green. Benwolf wears white pants with black markings that reach up his chest.
In Ultimate Alien, Benwolf's mane and tail have turned black and the inside of his mouth has turned red.
Benwolf wore the Omnitrix symbol on his waist in the original series and wears the Ultimatrix symbol on his chest in Ultimate Alien.
Benwolf has enhanced strength, supposedly being able to lift approximately 500 lbs. In addition to Benwolf's formidable claws, fangs and muscles, he can emit a strong and destructive green-colored glowing visible ultrasonic howl if the parts of his quadra-hinged muzzle are opened and a shout is released.