It is an evergreen shrub growing to 3-6 m tall, with stout, sparsely branched stems. The leaves are spirally-arranged, large, 20-50 cm in width and on a petiole up to 50 cm long, leathery, palmately lobed, with 7-9 broad lobes, divided to half or two-thirds of the way to the base of the leaf; the lobes are edged with coarse, blunt teeth. The flowers are small, white, borne in dense terminal compound umbels in late autumn or early winter, followed by small black fruit.
The name "Fatsi" is older Japanese, meaning 'eight' (in present-day Japanese hachi), referring to the eight lobes. The name "Japanese Aralia" is due to the genus formerly being classified within a broader interpretation of the related genus Aralia in the past.