The son of a butcher, he was trained as a locksmith. He served for several years in the merchant marine as a sailor (and then volunteered for the Navy), before taking up the acting profession in 1924.
Ensemble member of the Volksbühne Berlin (1933-45) and of the Hamburger Kammerspielen (1949 to 1954). In films often played humorous eccentrics or down-to-earth, guileless types. Perhaps best remembered for his rendition (along with Heinz Rühmann and Hans Brausewetter) of the hit song "Das kann doch einen Seemann nicht erschüttern" from the movie Bachelor's Paradise (1939).
Josef Sieber continued his career after the war before he achieved a second time huge popularity in the 50's, this time with sedated roles.
At the theater he appeared from 1924 where he worked as an actor and singer. His engagements led him through half Germany in the next years.
He made his film debut with "Pappi" (1934) and the movie was the prelude to a multitude of popular movies in which he took part in the 30's and 40's.