Eriosema luteopetalum is a small, evergreen, long-lived herb that grows from a woody base. It reaches 300–600 mm in height and forms a compact, upright, bushy shape. It grows slowly to moderately and retains its leaves throughout the year. The stems stand upright and branch at the base, creating a full appearance. They are covered with soft golden-brown hairs that lie flat against the surface, giving the stems a slightly rough texture. The leaves are made up of three leaflets. Each leaflet is oval to slightly spoon-shaped, usually 40–60 mm long and 30–40 mm wide, although inland plants often have narrower and more pointed leaflets. The upper surface of the leaf feels slightly rough, while the underside is densely covered with fine white hair. The veins are yellowish and very noticeable. At the base of each leaf are small, pointed, leaf-like structures called stipules, which are long-lasting and remain on the plant. The plant produces many flower clusters during the warm months, especially in spring. These clusters grow where the leaves meet the stem and rise well above the foliage. Each cluster may carry 24–45 flowers. The flowers are relatively large for the genus, greenish-yellow, and about 12–15 mm long. Small, boat-shaped bracts (modified leaves) sit beneath each flower and remain attached for a long time, adding to the plant’s showy appearance. After flowering, the plant develops small, rounded fruits covered with a mix of long yellowish hairs and short white hairs. As they ripen, the fruits turn brown and often remain on the plant even after releasing their seeds. The seeds are oval, hard, pale chestnut brown, and about 6 mm long.

Eriosema luteopetalum is most often confused with Eriosema dregei, but E. dregei has silvery stems and leaves (not golden-brown), smaller flowers, and shorter bracts that fall off quickly. The upper surface of E. dregei leaves also have silvery hairs, while E. luteopetalum has short yellowish hairs. It can also be confused with Eriosema latifolium, which differs in having much smaller flowers, shorter stipules, and narrower flower spikes.