Like all paradise kingfishers, this bird has colourful plumage with a red bill and long distinctive tail streamers.

The first formal description of the black-capped paradise kingfisher was by the English lawyer and zoologist Philip Sclater in 1877.

The genus Tanysiptera had been introduced by the Irish zoologist Nicholas Aylward Vigors in 1825.

[4][5] There are two subspecies:[6] The black-capped paradise kingfisher is 35–48 cm (14–19 in) in overall length including the tail streamers and weighs from 43 to 74 g (1.5 to 2.6 oz).

The adult of the nominate race has a black head, nape, ear-coverts and scapulars.