[8] They have a thick coat covered by white spots, that can be either light fawn or near-black, with off-white underparts stretching from the chin to the underside of the tail.

The spots are 5 to 20 mm (0.20 to 0.79 in) in diameter, and are found across the upper body and flanks, from the top of the head to the rump, but, unlike some other species of quoll, do not extend onto the tail.

[11] It likely became functionally extinct across its entire mainland range by the early 1960s, but remains widespread but patchy in Tasmania and Bruny Island.

[12] The eastern quoll is a solitary predator, hunting at night for its prey of insects, small mammals, birds, and reptiles.

[8] Although the majority of their diet consists of meat, they also eat some vegetable matter, including fruit during the summer, and grass year-round.

[8] Eastern quolls are nocturnal,[15] and spend the day resting in dens, although they may also use natural rock crevices or hollow tree trunks.

If intruders fail to leave quickly, then aggressive action escalates to chasing and wrestling with jaws while standing on their hind legs.

[2] The last eastern quoll specimen on the mainland was collected as roadkill in Nielsen Park, Vaucluse in Sydney on 31 January 1963,[22] however a taxidermied specimen provided to NSW National Parks and Wildlife Service in 2016 was reported to have been collected in 1989 or 1990 in the Gloucester region of NSW, indicating the species may have survived longer than the generally accepted 1960's decade of its mainland extinction.

In March 2016, a trial reintroduction of 16 eastern quolls from Mount Rothwell (Victoria), and Tasmania was conducted at Mulligans Flat Woodland Sanctuary in the Australian Capital Territory.

Adopting an adaptive management approach, the second and third trials involved only releasing females (preferring those carrying pouch young), which was met with increased survival (76.9% in 2017 and 87.5% in 2018).

The National Park was unfenced, but had undergone red fox baiting to prepare for the eastern quoll reintroduction.

However, due to threats including predation by residual red foxes, domestic dogs, and road mortality, no founders survived.