The magnificent Brush-tailed phascogale has an unusual ‘bottle brush’ tail, which is covered with long, silky, black colored hairs that can be erected on occasion. The head and body of this marsupial are grizzled grey, while the under parts are pale cream. Females of this species have a 'fake' pouch: they simply have a pouch area, exhibiting noticeably coarser, brown colored hairs with light tips. Males of this species show die-off shortly after mating, without even reaching 1 year old. Life expectancy of females is up to 3 years.
The Brush-tailed phascogales demonstrate activity during the nighttime hours, between dusk and dawn. These solitary animals forage only in the tree canopy. Home ranges of male individuals usually overlap with these of conspecifics, enlarging during the breeding season. Home ranges of female phascogales vary from 20 to 70 ha in size, without overlapping with these of unrelated females. Brush-tailed phascogales are generally arboreal, living in trees and rarely descending to the ground. When moving between trees, these excellent climbers can take long leaps of up to 2 meters. Their nests and shelters are located in tree hollows, typically lined with leaves, shredded bark as well as faeces. When disturbed, phascogales will give out an alarm call by producing a low, hissing sound. When encountering an opponent or rival, they are known to give out various chit-chit sounds