Smooth Sumac is a native large shrub that given space, can become a small tree, 10 to 15 feet high. The alternate leaf is 16 to 24" long, pinnately divided into 11 to 31 leaflets, very pale underneath, dark green above, and often toothed. The leaf stem (rachis) without fine hair. Leaflets are narrowed or rounded at the base, sharply pointed at the tip. Unlike Staghorn Sumac, twigs are smooth and not hairy and have spots. The flowers form in a compact, pyramid shape cluster at the end of the branches. The small 5-parted flowers are greenish-yellow and appear in a dense 8" high cluster. Fruit will appear on plants 3 to 4 years old. Smooth Sumac and Staghorn are very similar in that the flowers mature in late summer into a red hairy fruit 1/8" to 1/4" in diameter, called a drupe, which contains one seed. A cluster may contain 100 to 700 seeds. Most plants contain only male or female flowers, thus only the female plants will produce seeds, although some plants may have both flowers. The fruit clusters, if not eaten in season will often be visible over winter and in spring before leaf out, providing winter interest. The leaves in the autumn turn a brilliant red and may often be seen turning color in late summer. When growing in thickets, the tallest stems will be at the back with decreasing stem height forward, providing sunlight to all plants. These thickets are established from root sprouts from a vigorous root system. Fire and cutting encourage more growth, although those are also the two best control mechanisms short of chemicals.

Sumac fruit is a winter emergency food for large game birds and many songbirds have sumac in their diet. Deer will browse the stems and fruit. Sumac habitat is usually open fields and roadways, where there is sunshine and the soils are not wet. It will be crowded out by trees and larger shrubs. The species name, glabra, is Latin for "smooth".