The band was formed in 1996 by Simon Kvamm, Kristian Riis, Jonas Juul Jeppesen, and Søren Arnholt.

In 2000, the band debuted with their first studio album, Swimming Time, on the small label Martian Records.

[1] Nephew's third studio album, Interkom Kom Ind, was released in October 2006; it was certified 3× platinum in Denmark.

[4] In November 2012, Nephew released their fifth studio album, Hjertestarter, which topped charts in Denmark and on the Danish iTunes store for that month.

1-2-3-4-5 contains Nephew's five studio albums along with 15 bonus songs; early renditions of the songs "USADSB", "Mexico Ligger i Spanien", "Hospital", "007 Is Also Gonna Die", and "Hjertestarter; a remix of "Downtown Europe" by Ørtz/Mofus; an alternative version of "Worst/Best Case Scenario"; an early version of "Superliga"; the previously unreleased demo songs "Swedenborg" and "Marking Princess"; and pre-mixes of the previously unreleased "Pasfotografier", "Automatisk Mig", "Stop Nu Hjælp Nu", "The Day I Laminate My Heart", and "Jeg Kan Se".