Persoonia pertinax is an erect to spreading shrub that typically grows to a height of 1–2.5 m (3 ft 3 in – 8 ft 2 in) with smooth bark and young branchlets that are covered with greyish hair when young. The leaves are linear, flattened, 20–55 mm (0.79–2.17 in) long, 1–2.5 mm (0.039–0.098 in) wide and twisted through 90°. The flowers are arranged in groups of up to ten along a rachis up to 60 mm (2.4 in) long, each flower on a pedicel 3.5–7 mm (0.14–0.28 in) long, with a leaf or a scale leaf at the base. The tepals are yellow, hairy on the outside and 8–11 mm (0.31–0.43 in) long. Flowering occurs from January to March and the fruit is a flattened oval drupe 8.5–11 mm (0.33–0.43 in) long and 4.5–6 mm (0.18–0.24 in) wide.^[2][3][4][5]

Persoonia pertinax was first formally described in 1994 by Peter Weston in the journal Telopea from specimens collected by Robert Royce near Queen Victoria Spring in 1956.^[4][6] The specific epithet means "tenacious" or "unyielding", referring to the species' ability to survive in its arid environment.^[4]

This geebung grows in sandy soil in woodland near Cundeelee in the Coolgardie and Great Victoria Desert biogeographic regions of Western Australia.^[3][5]

Persoonia pertinax is classified as "not threatened" by the Government of Western Australia Department of Parks and Wildlife.^[5]