It is built upon a repeating riff and features lyrical references to Norse mythology, with singer Robert Plant's howling vocals mentioning war-making and Valhalla.

Though Led Zeppelin are typically regarded as an album-oriented group, "Immigrant Song" is one of the band's several hit singles.

[12]Six days after Led Zeppelin's appearance in Reykjavik, the band performed the song for the first time in concert during the Bath Festival.

[15] A phrase from the song was used as the title of Stephen Davis' biography of the band, Hammer of the Gods: The Led Zeppelin Saga.

[17] According to Jean-Michel Guesdon and Philippe Margotin:[1] "Immigrant Song" is one of Led Zeppelin's few releases on the 45 rpm single format.

[15] First pressings of the US single have a quote from Aleister Crowley inscribed in dead wax by the run-out groove: "Do what thou wilt shall be the whole of the Law.

In a contemporary review of Led Zeppelin III, Lester Bangs of Rolling Stone described "Immigrant Song" as the closest to being as classic as "Whole Lotta Love", praising the song's "bulldozer rhythms and Plant's double-tracked wordless vocal crossings echoing behind the main vocal like some cannibal chorus wailing in the infernal light of a savage fertility rite.

When the song was played live, Page included a lengthy guitar solo, which was absent on the recorded Led Zeppelin III version.