Dr. Farst started his career as a private practitioner but in 1969 took a position as veterinarian at the Columbus Zoo. Soon afterward he was called to do double duty and take on the responsibilities of the mammal curator. Dr. Warren Thomas, director of the Gladys Porter Zoo in Brownsville Texas asked Dr. Farst to take a job as associate director/veterinarian.
The opportunity to develop a collection from scratch and build a world-class zoo was the hook that brought him to Texas. Four years after his arrival Dr. Thomas left for the Los Angeles Zoo and Dr. Farst was named Managing Director. He was asked by the American Zoo Association to be the primary liaison between the Texas ranches working with the Black rhinoceros and the associations Rhinoceros Taxon Advisory Group.