Lillard was responsible for the creation of the International Schoolboy Fellowship in 1927, the first established international student exchange program for American schoolboys. He was chairman of the program which he formed in conjunction with headmasters from schools in England, France and Germany and eventually invited fifteen other New England prep schools to join as well. He took all boys who "made good" during the academic year on the annual cruise to France to partake in the exchange and brought English schoolboys to study at the Academy during the year. Lillard believed that "One American boy in a French community for a summer brings home a new understanding of French tradition and ideals, which he communicates to his schoolfellows. Friendship and tolerance are bred by intimacy, we cannot begin too young." After his years at Tabor, Walter "Cappy" Lillard went on to work for the United Nations in Vienna as the Chief of the Resettlement Division of the International Refugee Organization.