As an orchestral musician he played extensively with internationally renowned orchestras, such as the Berlin Philharmonic, the Royal Concertgebouw Orchestra and the Lucerne Festival Orchestra. In 2018 Sebastiaan was appointed Professor of Trombone at the Royal Conservatory in The Netherlands.

Collaborations with composers are an important part of the continuous search for new repertoire. Many new pieces have been written for Sebastiaan, for instance by Mike Svoboda, Theo Verbey, Nicholas Moroz, Jake Landau and Milika Kishino. Furthermore, Sebastiaan is always arranging existing repertoire, and searching for forgotten music. The concert programmes that emanate from this are often praised for their originality and unity, and for bringing out the lyrical side of the trombone. In 2010 he was named Young Musician of the Year Award, and since then he has won numerous first prizes at renowned international competitions, amongst others in New York (International Trombone Association) and Düsseldorf (Aeolus Wind Competition).

Sebastiaan always continues to develop himself as a musician, and in order to explore the academic side of his profession further he obtained a master’s degree in musicology from the University of Oxford in 2019, and is currently working on his PhD. Before that, he was part of the prestigious Herbert von Karajan Akademie der Berliner Philharmoniker, and in 2015 he finished his master studies with the highest distinction at the Conservatory of Amsterdam, where he studied with Jörgen van Rijen, Pierre Volders and Remko de Jager.Next to the intensive collaboration with his duo partner, pianist Andrea Vasi, Sebastiaan is a member of musical collective Ludwig (winning a Grammy Award for their first CD Crazy Girl Crazy), and of the New Trombone Collective, which also organises the biennial European Trombone Festival Slide Factory.