The Principal soloist of the Estonian National Opera Ballet Company (1971-1990) where he danced the main male roles in  the classical ballets and choreographies by the 20th century Estonian choreographers. In 1967, Tiit Härm founded the "Young Ballet" ensemble in Moscow where he was a soloist till 1971. As guest solist, he has performed at the Bolshoi Theatre and Mariinsky Theatre (1971-1990), and during all his career he has participated in various international tours and gala eveningsi in more than 70 different countries. He has performed the principal roles in ballet films and other movies. In the 80th of the 20th century he started to stage his own choreographies.

Since 1989, Tiit Härm has worked as Guest Ballet Master at Scottish National Ballet, Göteborgs Operan, Finnish National Opera, Bayerisches Staatsballett, Arenda di Verona, Aterbaletto, Reggio Emilia, Teatro San Carlo di Napoli, English National Ballet, Deutsche Oper am Rhein.

As guest choreographer, he has worked with  Grand Theatre de Bordeaux, Slovenian National Theatre Maribor, Teatro alla Scala, Scottish National Ballet, Göteborgs Operan, and Stora Theatre, Sweden.

He was the Ballet Director of the Estonian National Opera (1990-1992), the ballet master and professor at Teatro alla Scala and La Scala Ballet School (1992-1994, 1997-1999), Teatro dell'Opera di Roma and Scuola di danza del Teatro dell'Opera (1995-1997) and the Artistic Director of the Estonian National Opera Ballet (2001-2009).