Stuart-Houston was born William Patrick Hitler in the Toxteth area of Liverpool on 12 March 1911, the son of Adolf Hitler's half-brother Alois Hitler Jr. and his Irish wife Bridget Dowling. The couple met in Dublin when Alois was living there during 1909; they married in London's Marylebone district in 1910 and relocated back to Liverpool. The family lived in a flat at 102 Upper Stanhope Street, which was later destroyed during the last German air raid of the Liverpool Blitz on 10 January 1942. Dowling wrote a manuscript titled My Brother-in-Law Adolf, in which she claimed that Adolf had lived in Liverpool with her from November 1912 to April 1913 in order to avoid conscription in Austria. The book is largely considered a work of fiction, as Adolf was actually residing in the Meldemannstraße dormitory in Vienna at the time.
In 1914, Alois left Bridget and their son for a gambling tour of Europe. He later returned to Germany. Unable to rejoin his family due to the outbreak of World War I, he abandoned them, leaving William to be brought up by his mother. He remarried bigamously, but wrote to Bridget during the mid-1920s to ask her to send William to Germany's Weimar Republic for a visit. She finally agreed in 1929, when William was 18. By this time, Alois had another son named Heinz with his German wife. Heinz, in contrast to William, became a committed Nazi, joined the Wehrmacht, and died in Soviet captivity in 1942.
n 1933, William returned to what had become Nazi Germany in an attempt to benefit from his half-uncle's growing power. Adolf, who was now chancellor, found him a job at the Reichskreditbank in Berlin, a job that he held for most of the 1930s. He later worked at the Opel automobile factory and as a car salesman. Dissatisfied with these jobs, he again asked his half-uncle for a better job, writing to him with blackmail threats of selling embarrassing stories about the family to the newspapers unless his "personal circumstances" improved.
In 1938, Adolf asked William to relinquish his British citizenship in exchange for a high-ranking job. Suspecting a trap, William fled Nazi Germany and again tried to blackmail his uncle with threats. This time, William threatened to tell the press that Adolf's alleged paternal grandfather was actually a Jewish merchant. He returned to London, where he wrote the article "Why I Hate My Uncle" for Look magazine. He allegedly returned to Germany for a brief period in 1938. It is unknown exactly what William's role in late-1930s Germany was.
In January 1939, the newspaper magnate William Randolph Hearst brought William and his mother to the United States for a lecture tour. He and his mother were stranded when World War II began. After making a special request to President Franklin D. Roosevelt, William was eventually approved to join the United States Navy in 1944; he relocated to the Sunnyside neighbourhood of Queens, New York. William was drafted into the United States Navy during World War II as a pharmacist's mate (a designation later changed to hospital corpsman) until he was discharged in 1947. On reporting for duty, the induction officer asked his name. He replied, "Hitler." Thinking he was joking, the officer replied, "Glad to see you, Hitler. My name's Hess." William was wounded in action during the war and awarded the Purple Heart.
In October 2005, The History Channel broadcast a one-hour documentary titled Hitler's Family, in which William Patrick Hitler is described along with other relatives of Adolf Hitler.
Netflix aired a documentary titled The Pact: Le serment des Hitler (2014), directed by Emmanuel Amara, which was billed as a retracing of the life of Hitler, and an exploration of what became of the Hitler family line.