Kennedia retrorsa is a vigorous climbing herb covered with rust-coloured or white hairs. The leaves are trifoliate with broadly elliptic to more or less circular leaflets long and wide with stipules about long at the base. The flowers are arranged in groups of four to twenty in racemes up to long on a peduncle long with lance-shaped bracts at the base. The sepals are long and the petals are pinkish-purple or scarlet and long, the standard petal more or less circular. Flowering mainly occurs from September to December and the fruit is a densely hairy, flattened pod about long.