Swainsona fissimontana is a compact, erect or upright perennial herb, that typically grows to a height of up to and has densely softly-hairy stems. The leaves are imparipinnate, mostly long with 7 to 13 narrowly elliptic to elliptic leaflets, the leaflets long and wide with linear
stipules long at the base of the
petioles. The flowers are pink to dark purplish, arranged in racemes of 3 to 11 on a
peduncle long with egg-shaped
bracts long at the base. Each flower is long on a
pedicel about long, the
sepals are joined at the base to form a rounded tube about long with tapering lobes shorter than the tube. The
standard petal is about long and wide, the
wings long and the
keel long. Flowering usually occurs from August to December, and the fruit is an elliptic
pod long with the remains of the
style about long. ==Taxonomy and naming==