The group signed with the latter's Bad Boy Records to release their only album Last Train to Paris (2010), which was met with critical and commercial success.

Harper has predominantly written songs for other artists, such as Christina Milian's "Peanut Butter & Jelly", Charlotte Church's "Moodswings (To Come at Me Like That)", Aretha Franklin's "Put You Up on Game", Pussycat Dolls' "Painted Windows" and Ciara's "Pucker Up".

In 2009, Harper formed Diddy – Dirty Money, which included label boss Sean Combs and labelmate, former Danity Kane member Dawn Richard.

The band's follow-up single, "Love Come Down" was released that same day, although it was ultimately omitted from the Last Train To Paris album.

In November 2010, Harper and the group saw their furthest commercial success with the release of the album's fourth single "Coming Home" (featuring Skylar Grey), which peaked at number 11 on the Billboard Hot 100 and remains one of the best performing hip hop songs of that year.

Kalenna released a mix-tape called Chamber of Diaries on February 13, 2012, free of charge, consisting of thirteen tracks.