Triumfetta sonderi is a small, erect, slender, branched shrub 0.5-1 m tall. It has a woody rootstock and long slender stems covered in stellate (star-like) hairs. It is deciduous, dying back in winter and sending out new growth every spring. Leaves are alternate, simple, ovate with an acute apex and shallowly toothed margins, and are roughly hairy on both sides.

The flowers are small, star shaped, with light yellow petals and numerous stamens. They are produced in 2-4 flowered inflorescences during summer, from November to March. Fruits are attractive, pinkish-red, globose, up to 40 mm in diameter, bristly and covered with long fine hairs. The fruits remain on the bush for a long time, some fall off when they are ripe and lie on the ground, while some remain, dry, on the plant until it dies off in winter.