Mathias Weis was born in Lohr am Main. He received his first piano lessons at the age of eight. Through his encounters with blues, jazz and rock, his interest in improvised music was awakened at an early age. At first he approached this genre autodidactically, later he regularly took part in jazz courses of the Jeunesse musicale and received valuable suggestions there from Sigi Busch, Christoph Lauer and Ed Kröger, among others.

After graduating from high school in 1979, he was admitted to the Jazz Department of the University of Music and Performing Arts in Graz, at that time the only educational institution of its kind in Europe. In the subject jazz piano his teachers were Prof. Harry Neuwirth and Rob Franken, in the subjects jazz theory and jazz composition Prof. Dieter Glawischnig and Peter Herbolzheimer. Mathias Weis was also a guest student with Prof. Dr. Alfons M. Dauer at the Department of Afro-American Studies and with Prof. Ivan Eröd and Prof. Andrej Dobrowolski at the Department of Composition.

Following his jazz education, Mathias Weis first studied piano with Prof. Eugen Jakab at the Expositur Oberschützen of the Graz University of Music, before transferring to the University of Music Würzburg in 1983 to study school music. Mathias Weis was decisively influenced musically by his teacher in the main subject piano, Prof. Norman Shetler. From him he received important impulses in the field of song accompaniment.

After his state examination Mathias Weis worked as a freelance pianist, keyboardist and arranger in the fields of jazz, rock, pop and crossover. Concert tours, television appearances, radio recordings with, among others, Maria Joao, Gary Brooker (Procol Harum), Bobby Kimball (Toto), Jon Lord (Deep Purple), Pete York, Geoff Whitehorn, Johnny Logan and Joan Orleans, the Prague Philharmonic Orchestra and the Nuremberg Symphony Orchestra. Mathias Weis has written orchestral arrangements for the Heidelberg Philharmonic, the SWR Symphony Orchestra and the Brno Radio Symphony Orchestra. He has had engagements at the Graz Opera House, the Mainfranken Theater Würzburg and the Landestheater Coburg.

Mathias Weis has been a lecturer at the University of Music Würzburg since 1990. In September 1992 he took over the direction of the Music School Gemünden am Main. From 1997 to 2001, he was a member of the extended board of the Association of Bavarian Singing and Music Schools, responsible for the administrative district of Lower Franconia. For the winter semester 2006/07 he took over a substitute professorship in practical school piano playing at the University of Music Freiburg im Breisgau.