The son of a Swedish immigrant, William Albert Allard studied at the Minneapolis School of Fine Arts and the University of Minnesota with the hope of becoming a writer. Transferring to the University of Minnesota after only a year, he enrolled in the journalism program. He graduated in 1964 with a double major in journalism and photography...
Looking for work in the field of photojournalism, Allard met Robert Gilka, then National Geographic's director of photography, while in Washington, D.C., and was offered an internship. His most notable work as an intern included his photographs of the Amish for an article entitled "Amish Folk: Plainest of Pennsylvania's Plain People,"(published in August 1965). It is said to be regarded as landmark in the photographic evolution of National Geographic. His work led to a full-time position with the magazine.
In 1967, after just two years, Allard resigned from his position at National Geographic, feeling that he was unable to contribute to the issues of the time, such as the Vietnam War in a way that seemed possible at other magazines such as Life Magazine.
He continued to do assignments as a freelance photographer for National Geographic.
In 1982, Allard published his first book, "Vanishing Breed," a photographic essay documenting the "old American west". In 1989 he published his second work, a retrospective of his work entitled "The Photographic Essay". He continued to work for National Geographic, eventually taking up his second full-time position at the magazine.
Allard has also worked as a contributor to Magnum Photos.
Allard is one of the few photographers of his generation whose entire professional body of work is in color.