This is a common species in fynbos, open woodland, savannah and dry Acacia scrub.

The long-billed crombec is a small, nearly tailless bird 12 cm long and weighing around 16 g. Its upperparts are brownish grey-brown, and there is a pale grey supercilium, separated from the whitish throat by a dark eye stripe.

The long-billed crombec's nest is a large, hanging bag of grasses, spider webs, and plant fibres, which is attached to the lower limbs of a tree, often an Acacia.

This bird is usually seen alone, in pairs, or in family groups as it forages methodically from the bottom to the top of bushes and trees for insects and grass seeds.

The population size is believed to be large, and the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations).