His father was a successful opera singer before alcohol and an unhealthy lifestyle took their toll on his voice.
Through his father, he was an Austrian citizen at birth. He acquired German citizenship in December 1926.
His brother Leopold was born in 1895.
His father Georg Johann Bibert used "Robert Biberti" as a stage name before his son was born and ended up formally changing his name, resulting in the whole family using Biberti as a surname.
His father was Austrian.
His mother Elise Emilie (known as Emilie) was a voice and piano teacher originally from Herbesthal near Aachen.
Adoptive father (since 1973) of actress, author and blogger Ilse Biberti.