Swedishsongwriter and opera and pop singer. He has participated in Swedish versions of the musicals Les Misérables and Chess. In 2002, Kempe had a hit with Vincerò, where he mixed opera and disco.

Kempe has participated in Melodifestivalen twice as a performer. He entered Melodifestivalen 2004 with the song "Finally", a tribute to his favourite composer Benny Andersson and in 2005 together with Sanna Nielsen singing Du och jag mot världen.

In Melodifestivalen 2007, he co-wrote three songs. One was "Cara Mia", performed by Måns Zelmerlöw and another was "Vågar du, vågar jag", performed by Sanna Nielsen.

In Melodifestivalen 2008 he co-wrote the music and wrote the lyrics to the winning entry, "Hero", performed by Charlotte Perrelli.

Once again in 2009, he wrote the music and lyrics for the winning song "La voix" performed by Malena Ernman.

In 2011 he won Melodifestivalen for the third time, writing the Eric Saade entry "Popular".

In 2014 he won Melodifestivalen for a fourth time, writing Sanna Nielsen's entry "Undo".