As a voice actor Breitenfeld became known to a large audience as "Hoss Cartwright“ (Dan Blocker) in "Bonanza", who he dubbed in the Hamburg versions, along with Michael Chevalier, Martin Hirthe and Thomas Braut, and in Blocker's appearances in Margret Dünser’s "V.I.P.-Schaukel" and the detective film "Lady in Cement".