Because of their shared passion for the operas of Richard Wagner, they quickly became close friends and later roommates in Vienna while both sought admission into college.

As the only son of a self-employed upholsterer, Kubizek was expected to someday take over his father's business, but he secretly harboured dreams of becoming a conductor.

After the war, Kubizek accepted a position as an official in the municipal council of Eferding, Upper Austria and music became his hobby.

After seeing Hitler on the front page of the Münchner Illustrierte (circa 1920), Kubizek followed his friend's career with some interest, although he did not attempt to contact him until 1933 when he wrote to congratulate him on having become Chancellor of Germany.

"[9] When the tide began to turn against Hitler, Kubizek, who had avoided politics all his life, became a member of the Nazi Party in 1942 as a gesture of loyalty to his friend.

He was arrested by American forces shortly afterwards and held at Glasenbach, where he was imprisoned and interrogated by the U.S. Army Criminal Investigation Command.

In the epilogue, Kubizek wrote, "Even though I, a fundamentally unpolitical individual, had always kept aloof from the political events of the period which ended forever in 1945, nevertheless no power on earth could compel me to deny my friendship with Adolf Hitler."

Kubizek's second wife and widow, Pauline (1906–2001), was credited with having provided the Stocker Verlag with additional photographs for the book's fourth edition in 1975.