Dorn was born in Scheveningen, The Hague, Netherlands in 1901 and made his stage début at age 14 in Dutch productions. He graduated from the Academy of Fine Arts and Architecture in Scheveningen. Dorn served in the Queen Wilhelmina's Royal Guards in his native land.
Career
Holland
Dorn made his debut under the name of Frits van Dongen in Op Hoop van Zegen directed by Alex Benno. He had lead roles in De Big van het Regiment, The Cross-Patch, Op Stap, and Rubber. He appeared on stage in Camille, Ghosts and Journey's End. He also toured Java with a theatrical company.
Germany
Dorn moved to Germany where he appeared in The Tiger of Eschnapur and its sequel The Indian Tomb. He was also in Waltz Melodies, Covered Tracks, The Jumping Jack, and The Journey to Tilsit.
Hollywood
He moved to United States in August 1939, just a fortnight before World War II broke out. He went there at the urging of Henry Koster who had directed him in Holland. Koster was at Universal and Dorn made three films for that studio: Enemy Agent, Ski Patrol, and Diamond Frontier. Dorn went over to MGM where he had support roles in Escape and Ziegfeld Girl. Warners borrowed him to play the lead inUnderground. At MGM he had a support in Tarzan's Secret Treasure and they put him in a Dr. Kildare film, Born to be Bad, that had to be reshot when star Lew Ayres was fired due to being a conscientious objector. Dorn replaced him as a new doctor and the film was called Calling Dr. Gillespie. He had a support part in Random Harvest and was third billed in Reunion in France. 20th Century Fox gave him the lead role in Chetniks! The Fighting Guerrillas, playing Draža Mihailović. That studio kept him on to star in Paris After Dark. At Warner Bros he was fourth billed in Passage to Marseille. MGM gave him the lead in a B, Blonde Fever. At Warners he starred in Escape in the Desert, a remake of The Petrified Forest replacing Zachary Scott. At Republic, Dorn had the lead in I've Always Loved You, an expensive musical. In 1946 he appeared in a play with Claire Trevor, The Big Two. He was going to feature in Singapore but had to pull out when he fell ill with pneumonia. He had a good role in I Remember Mama at RKO, then did The Fighting Kentuckian with John Wayne at Republic. Dorn had support roles in Panther's Moon at Universal and Sealed Cargo at RKO.
Return to Germany
Back in Germany, Dorn starred in Behind Monastery Walls, Towers of Silence, Dreaming Lips and Salto Mortale.
Personal life
Dorn suffered from phlebitis, requiring surgery and causing a number of strokes. After an accident on stage, he retired in 1965 and spent the next 10 years of his life in his home in California. He was married twice. His first wife was Cornelia Maria Twilt. He was married to Dutch actress Marianne van Dam until his death.