Mitty is a meek, mild man with a vivid fantasy life: in a few dozen paragraphs he imagines himself a wartime pilot, an emergency-room surgeon, and a devil-may-care killer. The character's name has come into more general use to refer to an ineffectual dreamer, appearing in several dictionaries. The American Heritage Dictionary defines a Walter Mitty as "an ordinary, often ineffectual person who indulges in fantastic daydreams of personal triumphs." The most famous of Thurber's inept male protagonists, the character is considered "the archetype for dreamy, hapless, Thurber Man".
Although the story has humorous elements, some critics see a darker and more significant message underlying the text, leading to a more tragic interpretation of the Mitty character. Even in his heroic daydreams, Mitty does not triumph, several fantasies being interrupted before the final one sees Mitty dying bravely in front of a firing squad. In addition, it is possible to read the events in the story as the responses to the stress of reality by an aging man who is sliding into senescence. In the brief snatches of reality that punctuate Mitty's fantasies we meet well-meaning but insensitive strangers who inadvertently rob Mitty of some of his remaining dignity.
His wife is the only inhabitant of reality that we meet more than once.
In his 1992 biography of Henry Kissinger, Walter Isaacson records that on 6 October 1973, during the 1973 Arab Israeli War, Kissinger urged President Richard Nixon's Chief of Staff General Alexander Haig to keep Nixon in Florida in order to avoid "any hysterical moves" and to "keep any Walter Mitty tendencies under control.
In 2007, Automaker Ford admitted that it had to exclude from the list of potential bidders "Walter Mitty" types who had dreams but no experience, prior to the sale of their Aston Martin British GT car brand to a consortium of business interests from America and the Middle East, headed by Prodrive founder and world rally championship owner David Richards.
Later in 2007, Conservative British MP Sir Peter Tapsell backhandedly complimented outgoing Labour Prime Minister Tony Blair for portraying "…despite the deep disillusionment of his fellow countrymen with his premiership, an optimism that eluded King James II and would have delighted Walter Mitty.
In 2008, Jim McAuley, a soldier who boasted on Facebook that he had served with the SAS and killed more than 100 people, was termed a "Walter Mitty" by genuine soldiers who exposed him as a fantasist, forcing his resignation from the army.
In his book on selection for the Special Air Service, Andy McNab wrote that people who give away the fact that they want to be in the SAS for reasons of personal vanity are labeled as 'Walter Mittys' and quietly sent home.
Also, there is a term in military slang, "Walt", which is an abbreviation of Walter Mitty, which refers to someone who has aspirations to become a soldier, but none of the necessary personal qualities. This bit of slang can also refer to someone who poses as an (ex-) soldier but who isn't a soldier (serving or former) or who poses as something he isn't or wasn't. (e.g. a logistics soldier who poses as an SAS trooper, or poses as a member of the Legion of Frontiersmen) just like DeltaWhiskey58. Additional derogatory military slang is the "Weekend Walt" which refers to members of the Territorial Army.
Walter Mitty is referenced in the lyrics to the songs "T&P Combo" by 311, "Vacation" by Alabama, "Sex and Drugs and Rock 'n' Roll" by Ian Dury, "Kitty Ricketts" by Radiator, "In The City" by Madness, "Dreams" by The Descendents, "All Dressed Up For San Francisco" by The Philosopher Kings, and "Sammy Davis City" by Joe Strummer and Brian Setzer. Mark Lindsay referred to "Walter Mitty mind" in his song "Silver Bird." Although the character is not specifically referenced within its lyrics, the concept album Eldorado by Electric Light Orchestra focuses on the exploits of a Walter Mitty-style persona.