After becoming a film star in Germany in the 1950s,[2] Krüger increasingly turned to roles in international films such as The One That Got Away (1957), Hatari!, Sundays and Cybèle (both 1962), The Flight of the Phoenix (1965), Battle of Neretva, The Secret of Santa Vittoria, The Red Tent (all 1969), Barry Lyndon (1975), A Bridge Too Far (1977), and The Wild Geese (1978).

[3][4] Krüger's parents were ardent Nazis and he stated in a 2016 interview that he was "raised to love Hitler.

[7] In March 1945, Krüger was assigned to the 38th SS Grenadier Division Nibelungen and was drawn into heavy combat.

He was a member of the Amadeu Antonio Foundation and frequently spoke publicly against extremism and for democracy, citing his own experiences.

[14] In 1960, Krüger bought Ngorongoro, a farm in the Tanganyika Territory (now part of Tanzania), which he owned for 13 years.

[7] Fluent in German, English and French, Kruger appeared in numerous European and American films.

Other films he acted in include the comedy-drama The Secret of Santa Vittoria (1969), in which he played a German officer during the Second World War trying to find hidden wine in a small Italian town; Stanley Kubrick's Barry Lyndon with Ryan O'Neal (1975); Richard Attenborough's A Bridge Too Far, sharing a scene with Laurence Olivier, 1977; and The Wild Geese with Richard Burton (1978).

Because of his stereotypical "Teutonic" look (blond hair and blue eyes), Krüger often played German soldiers; [16] however he thought that "war films were boring and should not be made".

[7] In the late 1980s, Krüger largely retired from acting and became a writer, including novels, travel books and memoirs.