[6][7] The narrow-billed antwren has a disjunct distribution inland from the coast in the eastern Brazilian states of Bahia and Minas Gerais.

In part of Bahia it also occurs in mata-de-cipó, a biome characterized by a relatively open understorey and a few large emergent trees above a dense mid-storey.

It typically forages singly, in pairs, or in family groups, and sometimes as part of a mixed-species feeding flock.

It forages actively but methodically, picking at stems and limbs in woody vine tangles and on somewhat open branches while hitching along them.

The narrow-billed antwren's song is a "series of very high, loud 'tiúw' notes (2/sec over 8 sec)".

"Its habitats are being cleared for cattle pasture in central-south Bahia, and much of the forest in north-east Minas Gerais and adjacent south Bahia has been cleared for coffee plantations...[h]owever, the species seems to be able to cope with forest fragmentation, persisting in small areas.

It does not occur in any protected areas, but "substantial habitat harbouring viable populations of this species still exists in Jequié-Boa Nova region (Bahia) and at Almenara in Jequitinonha Valley (Minas Gerais), although neither area is formally protected".