In 1920, Müller's path intersected with the rising star of Adolf Hitler, courtesy of a business collaboration with Franz-Eher-Verlag and an introduction by Dietrich Eckart. This encounter marked the beginning of a lasting alliance, with Müller playing a pivotal role in disseminating Nazi ideology through publications like the Munich Observer, later rebranded as the Völkischer Observer, a propaganda mouthpiece for the regime.
Following Hitler's release from prison in Landsberg am Lech in December 1924, the pamphlet Mein Kampf was published by Franz-Eher-Verlag. This publication quickly became a bestseller, with Müller's printing company producing over 11 million copies by 1945.
Geli Raubal, Adolf Hitler's niece, lost her father at a young age, leading Hitler to become her guardian in 1923. They met for the first time in 1924 during Hitler's imprisonment in Landsberg am Lech. Initially studying medicine, Raubal later pursued singing lessons funded by Hitler, guided by his friend and fellow Wagner fan, the Kapellmeister Adolf Vogl.
In 1927, Geli moved in with Hitler and dropped her medical studies. In 1931 Geli commited suicide in their shared apartment. The circumstances surrounding her death remain mysterious, fueling speculation about their relationship.
With the outbreak of World War II, Müller's company became one of Germany's most modern printing and publishing enterprises, employing over a thousand workers and producing millions of copies of propaganda materials. In 1943 when Allied air raids destroyed a significant portion of Müller's company. Following Munich's occupation by American troops in 1945, Müller was arrested and later found dead in his cell in Stadelheim.
It is as if Müller was part of a gang of people named Adolf including Adolf Hitler, Adolf Eichmann, and Adolf Vogl.