Hess has composed and arranged for solo pianists, small groups, large string ensemble, big band, choirs and saxophone quartets.

He has also written music for the Danish film company Zentropa for Lars Von Trier's Melancholia (2011),[2] Tju Bang Film and the German Meeres Stille (2013)[3] as well as for radio (DR, NKR, Hungarian Radio), Den Kongelige Ballet, Det Kongelige Teater, dance companies, and installations in collaborations with visual artists.

[7] Hess is associate professor at the Rhythmic Conservatory in Copenhagen as well as the Art Director of Summersession, an educational program for professional musicians organized by JazzDanmark.

Among the list of artists Hess has worked with are Marc Mommaas, Tony Moreno, John Hebert, Jay Andersen, Christian McBride, Kenny Wollesen, Jeff Ballard, Lee Konitz, Benny Golson, Fela Kuti, Femi Kuti, Hal Willner, James Genus, Ambrose Akinmusire, Rez Abassi, Ben Monder, Satoshi Takeishi, Ben Street, Francois Moutin, Marilyn Mazur, Greg Hutchinson, Essiet Okon Essiet, Donny McCaslin, Jochen Rueckert, Jesper Lundgaard, Mads Vinding, Alex Riel, Lars Danielsson, Jacob Fisher, Johannes Weidenmuller, Tom Rainey, Cameron Brown, Sissel Vera Petersen, Hans Ulrik, Chris Minh Doky.

Ulla Henningsen, Julee Cruise, Jamey Haddad, Ed Neumeister, Danny Gottlieb, James Genus, David Liebman, Hal Crook, Harwie Swartz, Jean Luc Ponty, Marcello Pelletiri, Andrea Marcelli, Michael Blair, Kysia Bostic, Ed Howard, Youron Israels, Dennis Charles, Doug Raney, Cæcilie Norby, Debbie Cameron, Lars Hug, Bob Rockwell, Jukka Perko, Severy Pyssalo, Ed Thigpen, Kenneth Bager, Peter Poulsen, Copenhagen Art Ensemble, Annisette Koppel, and Ane Trolle.