Plants often forming large clumps, rhizomes, if present, with internodes shorter than 2 cm. Culms 1-3 m, often glaucous. Sheaths glabrous or pilose; ligules 0.4-2.5 mm; blades 5-50 cm long, (2)5-10 mm wide, usually pilose adaxially, at least near the collar. Inflorescence units usually only terminal; peduncles with 2-6(10) rames; rames 5-11 cm, exserted at maturity, usually purplish, sometimes yellowish; internodes sparsely to densely pubescent, hairs 2.2-4.2 mm, usually white, rarely yellowish.Sessile spikelets 5-11 mm, scabrous; awns 8-25 mm; anthers 3, 2.5-4.5 mm. Pedicellate spikelets 3.5-12 mm, usually well-developed and staminate. 2n = 20, 40, 60 (usually), 70, 80, 90.

Andropogon gerardii grows in prairies, meadows, and generally dry soils. It is a widespread species, extending from southern Canada to Mexico, and was once dominant over much of its range. It is frequently planted for erosion control, restoration, or as an ornamental; the records from Washington and central Montana reflect such plantings. It hybridizes with A. hallii, the two sometimes being treated as conspecific subspecies.