Jakob Stillmark began his musical education at an early age by playing the piano. At the age of nine he took his first composition lessons, in the course of which he wrote two works for school orchestra. From the age of fifteen he received lessons from Ernst-August Klötzke in Wiesbaden. Among other prizes, he won the German Orchestra Foundation prize for "best composition" at the orchestra workshop for young composers in Halberstadt. From 2013 to 2019 he studied composition with Isabel Mundry at the University of Music Munich and has been working as a freelance composer since receiving his master's degree.  He participated in numerous international master classes, where he received lessons from Toshio Hosokawa, Liza Lim, Younghi Pagh Paan and Peter Eötvös, among others. His works have already been heard in the chamber music series of the Munich Philharmonic, at the Munich Biennale, at the Munich Kammerspiele, at the Shanghai Academy of Music, at the Munich aDevantgarde Festival and at the Staatstheater Darmstadt. His orchestral work "heim-?" was premiered in June 2019 by the Deutsche Radio Philharmonie under the direction of Manuel Nawri.

Since September 2020, Stillmark has been a doctoral student at the Zurich University of the Arts and is a scholarship holder of the Friedrich Ebert Foundation. 

Stillmark is also active as a course instructor in the Daoist movement art Qigong.