[1][3] The specific name stewartae honours Margaret M. Stewart, an American herpetologist who wrote "Amphibians of Malawi" (1967)[4][5] and collected the type series,[2][5] originally identified as Phrynobatrachus gutturosus.

Males have a baggy vocal sac with a clear posterior flap.

[2] Phrynobatrachus stewartae occurs in marshy areas in dry forest and grassland at elevations of 800–1,200 m (2,600–3,900 ft) above sea level.

Breeding presumably takes place in marshes and well-vegetated, standing bodies of water.

While it exhibits a degree of tolerance to modified habitats, it is poorly understood to what extent this species is threatened by expanding agriculture.