Kronlund co-wrote Meja's million-selling debut album on Sony and co-wrote two songs for Britney Spears' second album, Oops!... I Did It Again. Kronlund co-wrote her hit single, "Lucky", with Max Martin and Rami and also co-wrote "Don’t Go Knockin' on My Door". He also has worked with Backstreet Boys, Lesley Roy and *NSYNC and, more recently, Robyn and Lambretta currently he is producing and co-wrote on the debut record for American artist Troy This! for Warner/Chappell Music Group in Sweden.
Kronlund also co-wrote two songs with Cyndi Lauper for her 2008 album Bring Ya to the Brink Kronlund also co-wrote the third single from Britney Spears' sixth album, Circus entitled, "If U Seek Amy", and "Till the World Ends", the second single from Femme Fatale, along with Max Martin.
In 2009, a joint between Alexander, the DJ Ali Payami and the teenage Swedish singer Mimmi Sandén worked in the song "Du" ("You" in Swedish). This song was selected by the national broadcaster of JESC in Sweden, TV4, and Mimmi performed it in the final of Junior Eurovision Song Contest 2009, which took place on 21 November 2009, on Kiev, Ukraine.