In 1929, Cunningham attended the Rowett Research Institute at the University of Aberdeen in Scotland and this marked the beginning of his lifelong interest in trace element nutrition.He returned to New Zealand with a PhD in copper metabolism to become a research officer in animal nutrition at Wallaceville Veterinary Laboratory in Upper Hutt.Upon his return to Wallaceville, he was appointed chief biochemist and section leader and concentrated on his main work of improving livestock production.In 1945, with the support of John Filmer, director of the Animal Research Division of the Department of Agriculture, Cunningham became superintendent of the Wallaceville station.The bacteriologist Sydney Josland worked under the direction of Cunningham at Wallaceville until he left to commence employment at the National Health Institute in Wellington in 1954.