He learned Esperanto in 1937, but started only in 1947, to use the language actively. Professionally, he worked as an Assistant Principal.
He gave various periodicals, including Esperanto en Skotlando (1949-1955), Esperanto (1955-1958, 1961-1962), Monda kulturo (1962-1963), Norda Pismo (1968-1972), La Britannic Esperantisto (1973-1999 ) and Fonto ( 1980-1987 ).
From 1977 to 1980, William Auld Deputy Chairman of the Universal Esperanto Association; 1979 to 1983 he was chairman of the Academy of Esperanto.
Auld was considered the most important Esperanto writer of his time. His main work is the epic La infana raso ( The child's race).