The pelage is relatively long and soft, the eyes big and dark, and the ears large and sparsely haired. The primary habitat of the Florida mouse is sand pine scrub at an early successional stage, but it also occurs commonly in pine-oak and scrubby flatwoods associations. It is a ground dweller and typically lives in burrows, favoring those of the gopher tortoise. Its diet consists of seeds, acorns, nuts, fungi, other vegetation, insects, and other small invertebrates.
Breeding occurs mainly in the fall and early winter.
Litter size ranges from one to six young, averaging three or four. The Florida mouse is threatened by widespread destruction of its restricted habitat. Much of the natural sand pine scrub and pine-oak associations on which the species depends have been converted to real estate developments, citrus groves, and pine plantations. Overprotection from fire has allowed vegetation in many other areas to become too dense and shady. The species already has disappeared from much of the Florida coast and interior and is becoming increasingly rare in its remaining habitat.