Following a stint as a newspaperman in Salt Lake City, the New York-born Margulies got his start in the movie business as an RKO Pictures publicist. He later joined Kirk Douglas' Bryna Productions company and became a production assistant on the 1960 epic Spartacus, whic starred Douglas and which was directed by Stanley Kubrick. Margulies' first solo production effort was the 1963 comedy 40 Pounds of Trouble, which starred Tony Curtis and Suzanne Pleshette.

After several other films, including Willy Wonka & the Chocolate Factory, he teamed with fellow producer David Wolper to produce the groundbreaking 1977 ABC mini-series Roots and its 1979 sequel Roots: The Next Generations. Roots, based on Alex Haley's book chronicling his African American ancestors' struggle for freedom, was the first TV drama to deal seriously and expansively with slavery.

His producer credits also included the highly rated 1983 mini-series The Thorn Birds, which starred Richard Chamberlain and Rachel Ward.

Margulies is survived by his wife, Ferne, her two children, and his two children.