[2] The sooty antbird was described and illustrated by the English ornithologists Philip Sclater and Osbert Salvin in 1868 and given the binomial name Percnostola fortis.

In the resulting rearrangement to create monophyletic genera, the sooty antbird was moved to the newly erected genus Hafferia.

Subadult males resemble adult females but are darker and grayer overall with a blackish gray crown.

[5][6][7][8][9][excessive citations] The sooty antbird inhabits the western Amazon Basin, where the nominate subspecies is by far the more widely distributed of the two.

Subspecies H. f. incanescens is restricted to the vicinity of Tonantins, Brazil, on the right bank of the Upper Amazon (Solimões) in western Amazonas state.

It favors areas with dense undergrowth, often along watercourses and in viny openings caused by fallen trees.

It typically forages singly, in pairs, or in family groups in dense vegetation, mostly on the ground and within about 1 m (3 ft) above it though occasionally to double that.

It captures prey by gleaning, reaching, or pouncing to the ground from a perch and less frequently by short sallies to foliage and stems.

[5][6][7][8][excessive citations] The sooty antbird's breeding season might extend year-round but definitely includes October to April in Ecuador and September to November in Peru.