It is a bright green cushion-like perennial herb of attractive compact growth habit. The plant is only a few centimetres high with a spread of approximately 40 cm. The common names, Two-flowered Knawel and Canberra Grass, have been applied to this species but are rarely used, the generic name Scleranthus being favoured. It may be planted successfully either singly or as a group, and complements rock features well by tending to cling to rocks and shape itself into crevices. The degree of compactness of individual plants is related to origin, with lowland forms exhibiting a more open habit.
Flowers are very small and in terminal pairs on a common peduncle .
The peduncle elongates from 1-4 cm and, being straw coloured, contrasts with the foliage in an unusual way. The fruit is a one-seeded hardened nutlet enclosed by the persistent calyx . The leaves of S. biflorus are rigid and crowded, 0.5-1 cm long, and occur towards the apex of the stems. The procumbent stems, being congested, give the plant a mound-like appearance. New plants may also be produced in time from seed.