It has more or less linear, pinnatipartite leaves with sharply-pointed teeth on the sides, golden yellow flowers in heads of about sixty, and glabrous, elliptical follicles.

Banksia subpinnatifida is a bushy shrub that typically grows to a height of 1.6 m (5 ft 3 in) but does not form a lignotuber.

Flowering occurs from September to October and the fruit is a glabrous, elliptical follicle 9–13 mm (0.35–0.51 in) long.

[2][3] This species was first formally described in 1964 by Charles Austin Gardner who gave it the name Dryandra subpinnatifida and published the description in the Journal of the Royal Society of Western Australia from specimens collected by Fred Lullfitz.

Banksia subpinnatifida is classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife but var.