[3][4] The green-bearded helmetcrest was formally described in 1840 by the French ornithologist Auguste Boissonneau from a specimen collected near Bogotá in central Colombia.

The tail is moderately long, forked, and coppery to bronzy green with much white on the outer feathers.

The adult female is similar to the male but lacks the crest and beard, and its underparts are buffy white with some greenish mottling.

[12] The green-bearded helmetcrest is found year-round in páramo but is suspected to move to high elevation forest in the dry season.

Its close relative the white-bearded helmetcrest migrates from the high páramo in the wet season to lower elevations in the dry and the green-bearded might also follow this pattern.

[12] The green-bearded helmetcrest feeds on nectar at a wide variety of flowering plants but is partial to Espeletia species.

It is thought that the short, fine bill of this bird and the other Oxypogon species is an adaption to facilitate extracting nectar from the numerous tiny florets of the flower heads of these plants.

That species makes a large nest of Espeletia fibers in cavities or below overhangs where it is protected from sun and rain.