Hansjörg Felmy was born on January 31, 1931, in Berlin, as the son of Air Force general Hellmuth Felmy and his wife Helene Felmy, born Boettcher. After working as a locksmith and a typographer, Felmy took actor's training from 1947 to 1949 at Hella Kaiser's. He then became a cast member at theatres in Braunschweig and Aachen. Felmy made his movie debut in 1956 as fighter pilot Robert Franke in Alfred Weidenmann's "Der Stern von Afrika" ("The Star of Africa") and played the headstrong officer candidate Hans Teichmann in "Haie und kleine Fische" ("Sharks and Little Fish"). Both films became box office hits and made Felmy one of the up and coming stars of 1950s German cinema.

But Felmy's most famous films were Kurt Hoffmann's satire "Wir Wunderkinder" ("Aren't We Wonderful") and Alfred Weidenmann's adaptation of Thomas Mann's novel "Buddenbrooks" ("The Buddenbrooks"), with Felmy in the role of Thomas Buddenbrook. Felmy was less prominent in the decline of German cinema during the 1960s. He starred in the Wilhelminian family chronicles "Die glücklichen Jahre der Thorwalds" ("The Happy Years of the Thorwalds"), but also in several Edgar Wallace crime movies. In 1966, Felmy appeared in Alfred Hitchcock's GDR spy movie "Torn Curtain", one of his few international films. Besides his movie work, Felmy regularly performed on stage, toured with plays and appeared in radio plays.

In 1974, Felmy took over the part of the police inspector for the WDR-"Tatort" and played the brooding Ruhr-area inspector Haferkamp with a melancholic air. Felmy who always had a say in the "Tatort" screenplays left the series in 1980 after 21 episodes. Besides and after "Tatort", Felmy sporadically appeared in crime series like "Sonderdezernat K1", "Die Männer vom K3", and "Ein Fall für zwei". Again for WDR, Felmy became the trustworthy head of security of Düsseldorf airport in the TV series "Abenteuer Airport".

Hansjörg Felmy passed away on August 24, 2007, in Landshut.