Sisson examines a shipment of railroad worms.
Sisson began his career as a fellow of National Geographic Society in 1942 and held it for forty six years. Also he worked as a chief national science photographer at the same society from 1981 to 1988. Since 1988 Robert was a freelance photographer.
Sisson was a member of Biological Photographers Association, National Audubon Society, National Geography Society, National Wildlife Federation, Society of Photograph Scientists and Engineers, New York Academy of Sciences, North America Nature Photography Association and Sigma Delta Chi.
On October 15, 1978 Robert Sisson married Patricia Matthews and adopted her son.