The malachite sunbird was formally described in 1766 by the Swedish naturalist Carl Linnaeus in the twelfth edition of his Systema Naturae under the binomial name Certhia famosa.

[2][3] He based his account on "Le grimpereau à longue queue du Cap de Bonne Espérance" that had been described and illustrated in 1760 by French zoologist Mathurin Jacques Brisson.

[5] The sunbirds are a group of small Old World passerine birds, and are placed within the family Nectariniidae, which is found across Africa, the Middle East and into South-east Asia.

The nominate N. f. famosa occurs mainly in South Africa, Lesotho and western Eswatini, although its range just extends into southern Namibia and Zimbabwe.

This large sunbird is found in hilly fynbos (including Protea stands as well as areas with aloes) and cool montane and coastal scrub, up to 2,800m altitude in South Africa.

The call is a loud tseep-tseep, and the male malachite sunbird has a twittering song, often accompanied by pointing its head upward and displaying his yellow pectoral tufts with his wings half open.

It was found that male birds display their pectoral tufts almost continuously throughout the night, whilst asleep, and one hypothesis is that these function as eyespots to deter nocturnal predators.