Ragnar was born in Kalmar, Sweden and is the son of district manager Hans Ragnar and the postal clerk Karin, née Pettersson. Ragnar trained at Dramatens elevskola (The Royal Dramatic Theatre's acting school) in 1962-65. The following year he got a job as director's assistant to Ingmar Bergman (on his stage production of Peter Weiss' play The Investigation), where Ragnar states he learned a lot on the art of acting and directing from "the master", just by watching and listening when Bergman worked with his actors and the script. In 1968 Per Ragnar had his breakthrough as an actor, earning much critical acclaim and audience praise for his performances in the Arnold Wesker "trilogy" staged that year in Sweden: Hönssoppa med korngryn (Chicken Soup with Barley), Rötter (Roots) and Jag talar om Jerusalem (I'm talking about Jerusalem). The same year he also made his film-breakthrough with Korridoren (The Corridor), Jan Haldoff's social commenting film on hospitals and the health care system in Sweden, where Ragnar plays a young doctor, new on the job, facing the dilemmas of prioritizing patients.