The name Walter Mitty and the derivative word "Mittyesque"[6] have entered the English language, denoting an ineffectual person who spends more time in heroic daydreams than paying attention to the real world, or more seriously, one who intentionally attempts to mislead or convince others that he is something that he is not.
The story had an influence on other humorists, notably Mad founder Harvey Kurtzman (who borrowed the story's sound effects), playwright George Axelrod (who employed Mitty-like fantasies in The Seven Year Itch) and animation director Chuck Jones (who created a Mitty-like child character for Warner Bros. cartoons).
When referencing actor Errol Flynn, Warner Brothers studio head Jack Warner noted in his autobiography, My First Hundred Years in Hollywood, "To the Walter Mittys of the world he [Flynn] was all the heroes in one magnificent, sexy, animal package".