Alongside Hietala’s film scores he has worked successfully with drama music in theaters and radio. Especially his music and soundworks in the Finnish National Theatre has been a great success among audiences and critics. His opera Ihmepoika A / Wonder boy A won the YAM Award for Best Opera in 2017.

Hietala is also known for his compositions and arrangements for symphony orchestras and has commissioned scores by Ensemble Intercontemporain Paris, Finnish Radio Symphony Orchestra, Helsinki Philharmonic Orchestra and UMO-Jazz Orchestra, BBC London Proms, to name a few.
Hietala has worked with the best Finnish conductors, classical and jazz instrumentalists and opera singers during his career and has his own group HumppAvanti inside the Avanti Chamber Orchestra originally founded by Esa-Pekka Salonen, Magnus Lindberg and Jukka-Pekka Saraste.

​In his works Hietala creatively combines different music genres; concert-, jazz-,improvisational-, ethnic-, rock- and electronic music, and is therefore held as the ”musical freethinker & maker” in the Finnish music scene.