[2][3] The green kingfisher was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae.

[4] Gmelin based his description on "Le martin-pêcheur vert et blanc" from Cayenne that had been described and illustrated in 1780 by the French polymath Comte de Buffon and also the "white and green kingfisher" that had been described in 1782 by the English ornithologist John Latham.

The population of Trinidad and Tobago, usually included with C. a. americana, has in the past been treated as subspecies C. a. croteta.

[11][9][2][12] The green kingfisher is about 20 cm (8 in) long and weighs about 35 to 40 g (1.2 to 1.4 oz); females are larger and heavier than males.

Birds in the northern and southern parts of its range, and those west of the Andes, are larger and heavier than the others, but the differences tend to be clinal.

The bill is black with some horn color at the base of the mandible and its legs and feet are dark gray.

Juveniles resemble females but are duller and have small buff spots on their crown and wing coverts.

It favors still or slow-moving water, and though it requires low vegetation for hunting perches it generally prefers relatively open habitat rather than dense forest.

In a study in Amazonia about half of the perches were bare snags and the rest were a mix of leafless and leafy trees and bushes.

[11] The prey is mostly small fish but includes crustaceans such as shrimp and also adult and nymph aquatic and terrestrial insects.

Both members of a pair excavate a nest burrow, almost always in an earthen bank of a stream or river.