Head and body length of M. rufogriseus is up to 780 mm (females) and 920 mm (males) with tail lengths of 790-875 mm. Males weigh up to 27 kg and females up to 16 kg. The upperparts are greyish brown with cream, the backs of the ears, neck and shoulders are rusty brown. The front paws and feet are black and the arms and legs are brownish. A faint white stripe is visible above the upper lip, and the underparts are whitish. The tail is grey with a darker tip.

M. rufogriseus is common in sclerophyll forests and coastal scrub, grazing and browsing on a wide variety of green shoots.

Activity is primarily nocturnal and crepuscular, M. rufogriseus is solitary. Mating occurs year round on the mainland, while Tasmanian individuals have a distinct birthing period from February to April. A single young is produced, becoming independent at 9 or 10 months.

They are distributed in SE South Australia, Victoria, SE Queensland, E New South Wales, Tasmania, King Isl and adjacent islands (Australia); introduced in England.