About the size of a cat, the Eastern ringtail possum is grey with white patches behind the eyes and on the belly, and orange-brown tinges on the tail and limbs. Its long tail has a white tip and it uses it like a fifth limb to climb and jump between connecting branches, fences and powerlines. The structure of its forefeet, with a gap between the second and third fingers, allows the possum to hold onto branches securely.
Almost exclusively tree-dwelling, the Eastern ringtail possum lives in in forests, woodlands, rainforests, dense scrub and suburban gardens. During the day, the Eastern Ringtail Possum sleeps in its spherical nest or 'drey' made from grass and shredded bark. It builds the drey in a tree hole, tree fork or dense vegetation, and several individuals may share the one nest.
The Eastern ringtail possum is nocturnal and eats a variety of leaves of both native and introduced plants, as well as flowers and fruits. By eating its own faecal pellets, it digests its food twice to extract the maximum amount of nutrients.
When the mother is feeding, the male carries the young on his back and cares for them. They are the only species of possum currently known where the male helps to care for the young.