Fox squirrels occur in a variety of color phases. In the Sandhills and Coastal Plain of North Carolina, they are grayish with various patches of black on the head and feet and white patches on the nose, paws and ear tips. Some animals are almost totally black with dark gray patches, and others are reddish or rust colored. The fox squirrel's total length measures 20 to 30 in, with a body length of 10 to 15 in and a similar tail length. They range in weight from 1.0 to 2.5 pounds. Fox squirrels are strictly diurnal, non-territorial, and spend more of their time on the ground than most other tree squirrels. They are still, however, agile climbers. They construct two types of homes called "dreys".

Because fox squirrels are solitary, their population densities are generally low even in areas where they are considered common. Fox squirrels are most abundant in open forest stands with little understory vegetation; they are not found in stands with dense undergrowth. Ideal habitat is small stands of large trees interspersed with agricultural land. The size and spacing of pines and oaks are among the important features of fox squirrel habitat. The actual species of pines and oaks themselves may not always be a major consideration in defining fox squirrel habitat. They are rare in heavily forested areas, unlike their close relatives grey squirrels.