Walter studied journalism at Vienna University before joining ORF as a freelance producer, writer and director. He began working on natural history films in 1985 and as versioning producer he premiered a new slot called Universum in 1987. Universum went on to become a hugely successful and popular strand, producing blue chip wildlife, nature and science documentaries with partners including the BBC, Nat Geo, Discovery, Smithsonian, NDR Naturfilm, WDR and Canal+.
Walter became head of the Universum team in 1994 and founded the ORF Natural History Unit, which is considered to be one of the leading brands in factual television worldwide. During his career Walter has won a number of awards, including an Emmy, several Pandas at Wildscreen and Teton awards at the Jackson Hole Wildlife Film Festival.
After 30 years at ORF Walter launched his own company, Terra Mater Factual Studios.