The Sooty-faced Finch occurs from Costa Rica south to northwesternmost Colombia, on the border with Panama. In this region, the species is apparently confined to the forested slopes of the Cerro Tacarcuna. The Sooty-faced Finch is generally found in pairs, sometimes in small family groups, and occasionally even joins mixed-species foraging flocks, e.g. when following army ants in search of the insects fleeing the swarm. Prior to a recent genetic-led revision, it and the Olive Finch (Arremon castaneiceps) were formerly regarded as the sole representatives of the genus Lysurus, and the two species are generally very similar, although Sooty-faced Finch differs in having a conspicuous white malar stripe, and a yellow patch on the central underparts. Both species are rarely found much above ground level, and most likely to be located by virtue of their vocalizations.