Born Herbert Charles Angelo Kuchacevich ze Schluderpacheru in 1917 in Prague, he emigrated to London in 1939, fleeing Nazi rule in his homeland. Already an actor by trade (he made a single film in Czechoslovakia), he began performing at the Old Vic and other English theatre companies. (He changed his long surname to Lom because it was the shortest he found in a local phone book.) Securing a seven-picture deal, he moved to Hollywood in the 1940s. His English-language film career began auspiciously. He played a psychiatrist in the hit 1947 James Mason vehicle "The Seventh Veil" (he had studied Freud and Jung as a young man) and was an empathetic London gangland kingpin in Jules Dassin's 1950 film noir "Night and the City."
Handsome, with large, dark, hypnotic eyes and a silky, poised Continental accent, Mr. Lom played a great many villains, but managed to instill his characters with depth, humor, magnetism and humanity. He was Napoleon Bonaparte in both "The Young Mr. Pitt" (1942) and King Vidor’s "War and Peace" (1956); a pirate chieftain who leads the slaves out of Italy in "Spartacus" (1960); and an incompetent crook in the Ealing Studios comedy "The Ladykillers," which also starred Peter Sellers. He had a rare starring role in 1948's "Double Alibi," playing a murderous trapeze artist
Mr. Lom's career playing the preeminent victim of Clouseau's idiocy began when he played Chief Inspector Dreyfus in "A Shot in the Dark" in 1964. He reprised the role in six more sequels, continuing as Dreyfus even after Sellers died. Though Sellers was the undisputed comic center of each film, Mr. Lom held his own, delivering a comic creation of near equal mastery. Confronted with Clouseau's pompous stupidity and ability to resolve complex cases in spite of himself, Lom's Dreyfus would twitch, fume, plot and occasionally accidentally shoot himself. In "The Return of the Pink Panther," Dreyfus rose to level of full-fledged villain, attempting to kill Clouseau, and threatening to blow up the planet if the world's leaders didn't deliver the hapless policeman into his custody.
On stage, Mr. Lom originated the role of the King in the original London cast of the musical The King and I in 1953. The production survives in its cast recording. In 1975, he played Napoleon yet again, in William Douglas-Home’s stage play Betzi.
Mr. Lom also wrote two historical novels, "Enter a Spy: The Double Life of Christopher Marlowe" and "Dr. Guillotin: The Eccentric Exploits of an Early Scientist." Mr. Lom was married and divorced three times. He is survived by two sons, Alec and Nick, and a daughter, Josephine.