Walter Rumer was born in Steinach am Brenner (Tyrol). He received his musical training with Josef Sorg in Innsbruck, Alois Posch in Vienna, and Bill Hunt in London. At an early stage, he developed a particular interest in historically informed performance practice as well as in cross-genre forms of musical expression. 

As a double bassist, Walter Rumer is regarded as one of the leading figures in his field. His artistic activity encompasses the classical concert repertoire, historically informed performance practice, contemporary music, as well as jazz and improvisation. A special focus lies on the historical double bass, whose performance practice and sound aesthetics he cultivates and further develops in a wide variety of musical contexts. 

For many years, Walter Rumer worked as a pedagogue and head of department for string and plucked instruments. Until 2025, he shaped orchestral projects at the Tyrolean State Conservatory for more than 15 years, featuring repertoire from the Baroque to the Viennese Classical period, in close collaboration with the concertmasters of the Akademie für Alte Musik Berlin. This work provided lasting impulses for the artistic and stylistic orientation of the training program. 

In addition, Walter Rumer taught at the Mozarteum University Salzburg from 1986 onward and led the double bass class at the Tyrolean State Conservatory in Innsbruck until 2025. Many of his students are now active internationally as professional musicians.