Rudnick's dubbing assignments included James Cromwell in several movies, Fulton MacKay in Vendetta for the Saint, Edward Hardwicke as Dr. Watson in the Jeremy Brett Sherlock Holmes series, Lionel Atwill in the 1939 The Hound of the Baskervilles, John Hostetter in Knightriders, and William Daniels on Boy Meets World. Animation roles include Ra's al Ghul on Batman: The Animated Series, Goldbug and others on Transformers, Scooter on Challenge of the Go-Bots, and the White King in the Alice in Wonderland anime.
Rudnick appeared in many German films and TV series from the 1960s onward, often as doctors or scientists. He appeared frequently on the crime series Tatort and was a regular on SOKO 5113 and Black Forest Hospital. English-language movies included The Net (1975, with Mel Ferrer and Elke Sommer) and 21 Hours at Munich (1976 TV movie, with William Holden).