The genus Wakaleo represents a close outgroup to the charismatic marsupial hypercarnivore Thylacoleo carnifex. While early species of Wakaleo were likely arboreal, or at least scansorial, the ecology of later species of Wakaleo is not well understood. Here we present descriptions of new postcranial material of W. vanderleueri and W. alcootaensis from mid- and late-Miocene fossil deposits from the Australian Northern Territory. New calculations suggest that these taxa were smaller than previously thought, around 30 kg and 50 kg respectively. The postcrania reveal increasing adaptation towards terrestrial locomotion and felid-like grappling predation within this lineage, in contrast to the more canid-like adaptations occurring at around the same time in the other major group of terrestrial marsupial carnivores, the thylacinids. This hypothesis seems to reflect similar patterns of divergent morphological adaptation towards large carnivorous forms among placental mammals, and highlights a greater diversity in the evolutionary history of medium to large sized marsupial carnivores during the Miocene in Australia than previously recognized.