The paradise riflebird is medium-sized, up to 30 cm long. The male is black with an iridescent greenish blue crown, throat and central tail feathers. It has a black curved bill, black feet, dark brown iris and yellow mouth. The female is an olive brown bird with barred blackish below. The diet consists mainly of insects and fruits.
In displays, the male extends his wings and fans them upward with its head behind the wings to expose his metallic green throat feathers. He then moves his head from side to side with open bill to show off his bright yellow mouth.