Described by Salvin in 1864 as Cardellina versicolor, based on specimens from Volcán de Guego, Totonicapam, and Chilasco, Guatemala. Sharpe (1885), followed by Hellmayr (1935) and Lowery and Monroe (1968), regarded the specimen from Chilasco as the holotype, but Warren and Harrison (1971) regard this specimen as a syntype. The Chilasco specimen and "other syntypes" are in the (British) National Museum (Natural History) (Sharpe 1885, Warren and Harrison 1971).
This species was transferred later to the genus Ergaticus Baird 1865, for which the type species was rubra (Red Warbler, Cardellina rubra). These two species, rubra and versicolor, were classified as the sole species in Ergaticus for over 130 years.
Lovette et al. (2010) constructed a phylogeny for Parulidae, based on a phylogenetic analysis of DNA sequence data from both mitochondrial and nuclear genes. This phylogeny indicated that rubra and versicolor were members of a clade that also included Cardellina rubrifrons (Red-faced Warbler), "Wilsonia" [Cardellina] canadensis (Canada Warbler), and "Wilsonia" [Cardellina] pusilla (Wilson's Warbler). Within this clade, canadensis and pusilla are basal members, rubra and versicolor are sister-species, and rubrifrons is sister to rubra + versicolor. Lovette et al. (2010) recommened that this clade be recognized as a single genus, for which Cardellina has priority. Consequently, Ergaticus versicolor returns to name under which it originally was described by Salvin, Cardellina versicolor.