Born in 1937 in Zürich, Thomas Kessler studied German and Romanic linguistics at the Universities of Zürich and Paris, composition with Heinz Friedrich Hartig, Ernst Pepping and Boris Blacher in Berlin where he founded his own electronic studio in 1965. In the following years, he was appointed as the director of the Berlin Electronic Beat Studio and musical director of the Centre Universitaire International de Formation et de Recherche Dramatiques in Nancy, France.

From 1973 until 2000 taught composition and theory at the Basel Music Academy where he created its electronic studio. Founder of Tage für neue Musik festival in Zürich, together with Gerard Zinsstag, and the live-electronic music festival Echt!Zeit with Wolfgang Heiniger in Basel. Currently lives in Basel and Toronto.