The species is a large (32–37 cm) cuckoo-shrike with a long square tail and all over dark grey plumage.

The south Melanesian cuckooshrike was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae.

[2][3] Gmelin based his description on the "New Caledonian crow" that had been described in 1781 by the English ornithologist John Latham in his book A General Synopsis of Birds.

[4] The naturalist Joseph Banks had provided Latham with a water-colour drawing of the cuckooshrike by Georg Forster who had accompanied James Cook on his second voyage to the Pacific Ocean.

[5] The south Melanesian cuckooshrike is now one of 22 species placed in the genus Coracina that was introduced in 1816 by French ornithologist Louis Pierre Vieillot.