Gary Barlow told The Sun November 20, 2008 that this anthemic song will make choosing the setlist for Take That's gigs easier. He said: "We've got so many songs to choose from to close live shows, but we always struggled for one to open with. Greatest Day is that song."

This was written by all four band members at Sarm West Studios in Notting Hill. Gary Barlow, who in Take That's previous incarnation was their chief songwriter, told The Irish Times November 8, 2008 how they wrote this song and the rest of The Circus together. He explained: "We're four people in this band, so when we go and record an album it's not one or two people recording, it's the whole band in there, and there's some part of everybody on every song." Mark Owen added: "There were a couple of keyboards and a couple of guitars, and we were all on different parts, getting different chords, trying to be heard and get our ideas across."

This was Take That's 11th UK #1, making them the third most successful group in British chart history. Only the Beatles (17) and Westlife (14) have achieved more.

Take That filmed the song's video in the downtown area of Los Angeles, whilst visiting their Californian based producer John Shanks.