His father was a sea captain, but he refused to allow his son to became a sailor like him. But that could not scare the 14-year old Rydeberg, and at the age of 14, he was steward on a boat to Hull, UK, and the next year he was a sailor on a ship to Lagos, Africa. He got a job as an office clerk, where he met his fourth wife, 'Eugenie Trullemans' whom he married 25 years later. He didn't like the office work and began acting at the Lorensberg Theatre in Gothenburg, which led to acting at the Royal Dramatic Theatre's acting school. His teachers was far from impressed with his acting, in fact he almost had to leave the school. In 1931 he became an actor at the Blanche Theatre in Stockholm. In 1936 he got a contract with Svensk Filmindustri and made two movies with Gustaf Molander, Dollar (1938) and Visage de femme (1938). He played against Viveca Lindfors in Tänk, om jag gifter mig med prästen (1941). The two had a love affair, and they met again in Appassionata (1944). During the 1950s he worked with Arne Mattsson on several movies: Pour les ardentes amours de ma jeunesse (1952), Le pain de l'amour (1953), 0047527 and Hemsöborna (1955). The 1960s was filled with work at the Royal Dramatic Theatre in Stockholm, where he appeared in plays by August Strindberg, William Shakespeare and Lars Forssell.