With Liverpool, Liddell won a league championship in 1947 and featured in the club's 1950 FA Cup Final defeat by Arsenal. He represented Scotland at international level on 29 occasions. While serving as a Royal Air Force navigator during the Second World War, Liddell continued his career by appearing in unofficial games for Liverpool and guesting for various teams in the United Kingdom and Canada. After his retirement from football, in 1961, Liddell occupied himself as a Justice of the Peace (from 1958), bursar of Liverpool University, and voluntary worker.