Swanagan began his career when he joined the Columbus Zoo as an intern in 1980. The zoo's director, Jack Hanna, met Swanagan in 1978 while he was working at a nearby hotel as an Ohio State University science education student. OSU professor Dr. Barbara Thomson assigned Swanagan to the Columbus Zoo & Aquarium for a semester letter grade. Hanna hired Swanagan as a zookeeper two years later. In 1982, Hanna promoted Swanagan to the position of education director, a job that he held until 1987.
