Within a few years, Wallis became involved in the production end of the business and would eventually become head of production at Warners. In a career that spanned more than fifty years, he was involved with the production of more than 400 feature-length movies.
Among the many great movies he produced was Casablanca, one of the most honored movies in Hollywood history, as well as True Grit, for which John Wayne won the Academy Award for Best Actor of 1969. Wallis left Warner Bros. in 1944 to work as an independent producer, enjoying considerable success both commercially and critically. Among his financial hits were the Dean Martin and Jerry Lewis comedies, and several of Elvis Presley's movies.
Hal Wallis received sixteen Academy Award nominations for Best Picture, winning for Casablanca in 1943. For his consistently high quality of motion picture production, he was twice honored with The Irving G. Thalberg Memorial Award. He was also nominated for seven Golden Globe awards, twice winning awards for Best Picture. In 1975, he received the Golden Globe Cecil B. DeMille Award for lifetime achievement in motion pictures.