It is the first German-language adaptation of a 1928 novel by Erich Maria Remarque, which was also made into a best picture-winning film in 1930.
Accepting his award, Berger thanked the film's young star, Felix Kammerer, who was with him on stage.
"This was your first movie, and you carried us on your shoulders as if it was nothing," Berger said.
“All Quiet on the Western Front tells a story of a young man who, poisoned by right-wing political nationalist propaganda, goes to war thinking it's an adventure, and war is anything but an adventure," producer Malte Grunert said in his acceptance speech for best film at the BAFTA awards last month.
The film "is in fascinating dialogue with not just its source material, but the long history of warfare and cinema about war and atrocities," Sight & Sound wrote in its review, saying the film also owed a debt to films like ‘1917’, ‘Saving Private Ryan’ and ‘Black Hawk Down’.
The film was nominated in nine categories this year, including best picture. Only ‘Everything Everywhere All at Once’, with 11 nods, had more.
‘All Quiet on the Western Front’ beat out international film nominees ‘EO’ from Poland, ‘The Quiet Girl’, from Ireland; Belgian film ‘Close’; and ‘Argentina, 1985’ from Argentina.