In World War I, Wellman enlisted in the Norton-Harjes Ambulance Corps to serve as a driver in Europe. While in Paris, Wellman joined the French Foreign Legion and was assigned on December 3, 1917 as a fighter pilot and the first American to join N.87 escadrille in the Lafayette Flying Corps (not the sub-unit Lafayette Escadrille as usually stated), where he earned himself the nickname “Wild Bill” and received the Croix de Guerre with two palms. N.87, les Chats Noir (Black Cat Group) was stationed at Lunéville in the Alsace-Lorraine sector and was equipped with Nieuport 17 and later Nieuport 24 “pursuit” aircraft. Wellman’s combat experience culminated in three recorded “kills”, along with five probables, although he was ultimately shot down by German anti-aircraft fire on March 21, 1918. Wellman survived the crash but he walked with a pronounced limp for the rest of his life.

Maréchal des Logis (Sergeant) Wellman received a medical discharge from the Foreign Legion and returned to the United States a few weeks later. He spoke at War Savings Stamp rallies in his French uniform. In September 1918 his book about French flight school and his eventful four months at the front, titled Go Get ‘Em! (written by Wellman with the help of Eliot Harlow Robinson), was published. He joined the United States Army Air Service but too late to fly for America in the war. Stationed at Rockwell Field, he taught combat tactics to new pilots.

Wellman made his uncredited directorial debut in 1920 at Fox with The Twins of Suffering Creek. The first films he was credited with directing were The Man Who Won and Second Hand Love, released on the same day in 1923. After directing a dozen low-budget ‘horse opera’ films, Wellman was hired by Paramount in 1927 to direct Wings, a major war drama dealing with fighter pilots during World War I that was highlighted by air combat and flight sequences. The film culminates with the epic Battle of Saint-Mihiel. In the 1st Academy Awards it was one of two films to win Best Picture (the other was Sunrise), although, due to tensions within the studio regarding time and budget overages, Wellman wasn’t invited to the event.

Dorothy starred in Wellman’s 1933 film Wild Boys of The Road and had seven children with him, including actors Michael Wellman, William Wellman Jr., Maggie Wellman, and Cissy Wellman. His daughter Kathleen “Kitty” Wellman married actor James Franciscus, although they later divorced. His first daughter is Patty Wellman, and he had a third son, Tim Wellman.

Wellman reportedly worked fast, usually satisfied with a shot after one or two takes. Despite his reputation for not coddling his leading men and women, he coaxed Oscar-nominated performances from seven actors: Fredric March and Janet Gaynor (A Star Is Born), Brian Donlevy (Beau Geste), Robert Mitchum (The Story of G.I. Joe), James Whitmore (Battleground), and Jan Sterling and Claire Trevor (The High and Mighty). Regarding actors, Wellman in a 1952 interview stated, “Movie stardom isn’t about acting ability, it’s personality and temperament”. He then added, “I once directed Clara Bow. She was mad and crazy but what a personality!”

While he was primarily a director, Wellman also produced 10 films, one of them uncredited, all of which he also directed. His last film was Lafayette Escadrille (1958), which he produced, directed, wrote the story for and narrated. He wrote the screenplay for two other films that he directed, and one film that he did not direct: 1936’s The Last Gangster. He also wrote the story for A Star Is Born and received a story credit for its remakes in 1954, 1976, and 2018.

Wellman won a single Academy Award, for the story of A Star Is Born. He was nominated as best director three times: for A Star Is Born, Battleground and The High and Mighty, for which he was also nominated by the Directors Guild of America as best director. In 1973, the DGA honored him with a Lifetime Achievement Award. Copies of both Wings and The Story of G.I. Joe are preserved in the Academy Film Archive. Wellman also has a star on the Hollywood Walk of Fame, at 6125 Hollywood Blvd.

Decades after Wellman’s death, William Jr. wrote two biographies about his father, The Man and His Wings: William A. Wellman and the Making of the First Best Picture (2006) and Wild Bill Wellman—Hollywood Rebel (2015). Fellow filmmakers have also examined Wellman’s career. Richard Schickel in 1973 devoted an episode of his PBS series The Men Who Made the Movies to Wellman, and in 1996, Todd Robinson made the feature-length documentary Wild Bill: Hollywood Maverick.

William Wellman in 1975 died of leukemia at his Brentwood home in Los Angeles. He was cremated, and his ashes were scattered at sea. His widow Dorothy, at age 95, died on September 16, 2009 in Brentwood, California.