Mikis Theodorakis, the renowned Greek composer and Marxist firebrand who waged a war of words and music against an infamous military junta that imprisoned and exiled him as a revolutionary and banned his work a half century ago, died on Thursday. He was 96.

The cause was cardiopulmonary arrest, according to a statement on his website. News reports in Greece said he died at his home in central Athens.

Mr. Theodorakis was best known internationally for his scores for the films “Zorba the Greek” (1964), in which Anthony Quinn starred as an essence of tumultuous Greek ethnicity; “Z” (1969), Costa-Gavras’s dark satire on the Greek junta; and “Serpico” (1973), Sidney Lumet’s thriller starring Al Pacino as a New York City cop who goes undercover to expose police corruption.......