Growing to 8 m (26 ft) tall and broad, it is an evergreen shrub or small tree.

It produces many racemes of pea-like yellow flowers[1] from August or as early as May through to October.

When young S. microphylla has a divaricating and bushy growth habit with many interlacing branches, which begins to disappear as the tree ages.

[2] The cultivar Sun King 'Hilsop' has gained the Royal Horticultural Society's Award of Garden Merit.

[8] Studies of accumulated dried vegetation in the pre-human mid-late Holocene period suggests a low Sophora microphylla forest ecosystem in Central Otago that was used and perhaps maintained by giant moa birds, for both nesting material and food.