 Hartberg attended Foss Upper Secondary School (1991–94), on the Music program together with the artists Bertine Zetlitz, Jannike Kruse, Kate Havnevik and the author Markus Midrè.He studied music at Norwegian Academy of Music 1995-99.Hartberg was noticed as early as 15–16 years old as a bass player on the jazz scene connected to «Oslo jazzhus» in "Toftesgate".