AbstractRhizoma peanut (Arachis glabrata Benth.) is an important hay crop in the southern United States. Since rhizoma peanut is a warm‐season perennial legume, it remains dormant during the cool season. Overseeding rhizoma peanut during the cool season could optimize land productivity per unit area throughout the year. However, the effect of overseeding on rhizoma peanut performance in the following growing season is unknown. This study evaluated different combinations of rye (Secale cereale L. ‘FL401’) and/or ryegrass (Lolium multiflorum Lam. ‘Prine’) mixed or not with clovers (Trifolium spp.) overseeded on dormant ‘Florigraze’ rhizoma peanut. Rye–clover mixtures resulted in greater herbage accumulation (6,040 lb ac−1 yr−1) than grass monocultures, clovers, and rye–ryegrass mixtures. However, rye–clover mixtures had similar herbage accumulation to rye–ryegrass–clovers (5,640 lb ac−1 yr−1) and ryegrass–clovers (4,560 lb ac−1 yr−1). Crude protein (CP) concentration in grass was greater for rye and rye–ryegrass (9.8%, for both) than in ryegrass monoculture (8.2%), nonetheless, it was similar to other treatments (9.1%, on average). Ryegrass and ryegrass–clovers resulted in the greater in vitro digestible organic matter (IVDOM) for the grasses (81%, on average) than all other treatments (70%, on average). Overseeding rhizoma peanut did not affect its herbage responses. On average, herbage accumulation, CP, and IVDOM for Florigraze rhizoma peanut in the first harvest following the overseeding treatments were 3,845 lb ac−1, 14.2%, and 75.7%, respectively. Results indicate that overseeding cool‐season grass–legume mixtures would optimize forage production per unit area and improve forage nutritive value without compromising rhizoma peanut herbage responses in the growing season.