Protea curvata is a slender, evergreen tree that can reach up to 8 m high, and produces a trunk of 100–300 mm in diameter. Bark is brown when young and black when mature. The leaves of the current year are clustered, leathery, hairless, glaucous and narrowly oblong-lanceolate, sickle shaped, 110–200 mm long and 8–16 mm wide. 

Protea curvata produces globose flower heads that are 50–70 mm in diameter. The involucral bracts are deep pink, with silky to velvety hairs on the margins and hairless below; the outer series of bracts are ovate, 7–30 mm long and 10–15 mm wide, the inner series are ovate to oblong, 20–30 mm long and 8–16 mm wide. The perianth is 50–60 mm long, pink, with short, pale hairs. Male and female parts are carried in the same flower. The female consists of a stigma, style and ovary, and the style has a modified tip that carries the pollen when the flower is open, called the pollen presenter. The style is pink, straight, about 60–65 mm long and the pollen presenter is 15 mm long. The male consists of anthers that are attached to the perianth. Before the flower opens, the anthers press their load of pollen onto the pollen presenter, and when the flower opens, the perianth falls away. 

The plant begins flowering in autumn (May) and continues until late spring (October) and flowers with abundance in midwinter (June and July). The heads will remain open and shed the seeds 4 months after flowering, in early summer (October to December). 

Protea curvata is similar to a form of P. caffra, previously known as P. rhodantha var. falcata, that occurs in the east of Claremont Vale. They both have sickle-shaped leaves and a similar growth habit, but the latter has typical P. caffra flower heads.