Plants cespitose, with knotty rhizomes no more than 2 mm thick. Basal rosettes well-differentiated; blades few, small, ovate to lanceolate. Culms 24-80 cm, glabrous or puberulent; nodes sparsely spreading-pilose; internodesmostly elongated, glabrous or puberulent; fall phase with a few suberect branches from the lower and midculm nodes, blades slightly reduced, secondary panicles partially exserted. Cauline leaves 3-4; sheaths not overlapping, with ascending papillose-based hairs; ligules 0.3-0.5 mm, membranous, ciliate, cilia longer than the membranous portion; blades 5-15 cm long, 7-13 mm wide, ascending to erect, sparsely to densely pubescent with papillose-based hairs, with 9-11 prominent major veins and 25-50 minor veins, bases truncate to cordate, margins with papillose-based cilia. Panicles 6-10 cm long, 3-5 cm wide, their length usually less than twice their width, eventually well-exserted, with 20-40 spikelets; branches spreading to ascending. Spikelets 3.3-3.8 mm long, 1.6-2mm wide, ellipsoid-obovoid, turgid, pubescent, hairs papillose-based, apices rounded. Lower glumes about 1.8 mm, narrowly triangular; lower florets staminate; upper florets mucronate. 2n = 18.
Dichanthelium leibergii grows primarily on prairie relics, butis occasionally found in sandy woodlands. The primary panicles are produced from mid-May through July, the secondary panicles from late June to September. Sterile putative hybrids with D. acuminatum and D. xanthophysum are occasionally found.