This species inhabits water-associated areas such as riparian woodlands, closed forests, marshlands and watercourses. It also occurs in dry, open sclerophyll as well as dry rock areas and appears to thrive in areas of anthropogenic disturbance, particularly in mosaic habitats of grazing and patches of remnant bushland. It is occasionally arboreal. It is a flexible, generalist predator that feeds on frogs and small mammals (possum, bandicoot, antechinus, rats, mice), taking also fish (eel, trout), amphibians and bird hatchlings on certain islands. The species is recorded to be cannibalistic on King Island (Cogger 2014). It is primarily a diurnal and crepuscular species but is sometimes nocturnal in hot weather. Mating presumably occurs from December to April with two peak mating seasons (spring and autumn). The species is viviparous with 23 young on average (ranging from 17 up to 109 young) and it reproduces infrequently. A captive female was documented producing its first litter at 47 months of age. (Shine and Charles 1982, Shine 1977, Fearn et al. 2012, Cogger 2014).

This species is widespread but disjunctly distributed in southern Australia, in southeast Western Australia, south-eastern South Australia, south-eastern Queensland, highlands, central and southern New South Wales, much of Victoria, Tasmania and the islands of the Bass Strait (Wilson and Swan 2013, Cogger 2014).

This species can be found within protected areas. Mirtschin and Davis (1985) point out that although the overall numbers of Notechis scutatus are likely to have been reduced drastically due to habitat alteration (river level control, replacement of stone walls by wire fences, drainage of lakes and swamps for farmland) but is still abundant in many areas (e.g. Melbourne region). Under the names N. ater ater and N. a. serventyi, subpopulations of this species are listed as Vulnerable by the Commonwealth government (N. a. ater) and the Tasmanian government (N. a. serventyi) (Wilson and Swan 2013).