[1] He received first piano lessons by the composer Hansmaria Dombrowski [de] in Stettin when he was 8 years old.
In 1941, he began studies at the Mozarteum in Salzburg with Walter Lampe (composer) (piano) and Friedrich Frischenschlager (theory).
He continued after the war at the Hochschule für Musik Freiburg with Harald Genzmer (composition) and Edith Picht-Axenfeld (piano).
As a student of Harald Genzmer and in the wake of Paul Hindemith, Bartók and Stravinsky, Zehm composed in extended tonality.
[2] His Mass Deutsche Messe mit Einheitsliedern was premiered on 15 September 1968 in Wiesbaden by the Chor von St. Bonifatius and members of the Hessisches Staatsorchester, conducted by Peter Kempin.