"Keep the faith" was co-written by the former Boøwy lead vocalist and lyricist Kyosuke Himuro (who later released a cover version of the song on a 2008 compilation of his) and SPIN, a frequent songwriter for the group.

[3] It stayed on the charts for 16 weeks and was certified as the fifth best-selling single of 2007 with total reported sales of over 459,919 units by the end of its chart-run.

KAT-TUN became one of only two artists in Japanese music history to sell more than 300,000 copies of five or more consecutive singles in the first week (the other being another JE boy band and senpai, KinKi Kids).

[4] The single was certified platinum by the Recording Industry Association of Japan in November 2007 denoting more than 250,000 shipments.

The song was honored at the 22nd Japan Gold Disc Awards when it was placed on the "Best 10 Music Singles (Domestic)" list alongside "Yorokobi no Uta".