 During 1977-78, Schlee was an auditor in Olivier Messiaen's composition class in Paris and studied privately with composer and organist Jean Langlais.Upon returning to Austria, he also studied with composer Francis Burt.From 1986 to 1989 Thomas Daniel Schlee was dramatic advisor for music at the Salzburger Landestheater, 1988-90 he taught at the University for Music and Performing Arts Vienna and at the Institute for Musicology at the Salzburg University.