Alphons Diepenbrock was born on 2 September 1862 in Amsterdam and grew up in a Catholic family of five children. As a child, Diepenbrock was attracted to music and he played the piano and the violin. His parents did not support his wish to go to the conservatory and Diepenbrock went to study classical languages instead. He composed in his spare time.
In 1888 he took his doctoral degree on a thesis on Seneca. In the same year he was appointed as a classics teacher at the gymnasium in Den Bosch. In his spare time, he was still composing, as well as writing essays on various subjects, such as music, painting, literature, philosophy, social history and politics for journals such as De Nieuwe Gids and De Kroniek.
Dissatisfied with the educational system of that time and the uninspiring environment of the town where he was living, Diepenbrock moved to Amsterdam in 1895. Here, he gave private lessons in classical languages and started to focus more on composition. In 1895 he married Elisabeth de Jong van Beek en Donk (1868-1939). They had two children: Joanna (1905-1966) and Thea (1907-1995).
As a composer, Diepenbrock was self-taught. Out of a feeling of insecurity, he was always polishing his music. On the other hand, the collaboration with directors and singers who were convinced of the qualities of his work, always fortified and helped him. Diepenbrock died in Amsterdam on 5 April 1921.