Cyril Isaac Magnin (July 6, 1899 – June 9, 1988) was an American businessman from San Francisco, California.

[2] His paternal grandfather, Isaac Magnin, was a Dutch-born frame carver and gilder.

[3] His cousin, Edgar Magnin, was the rabbi of the Wilshire Boulevard Temple, a Reform Jewish congregation.

[1] He was president of the Port of San Francisco and was instrumental in establishing such internationally renowned institutions as the Asian Art Museum, the American Conservatory Theater and the California Culinary Academy, serving as head of the California Museums Foundation.

[1][2] He appeared in the films Foul Play, as Pope Pius XIII, and Maxie, as Mr. San Francisco.

Throughout the 1950s and 1960s, Magnin was one of a quartet of wealthy San Francisco Jewish contributors to Democratic candidates, appreciatively called "The Green Machine" by career politicians,[6][failed verification] the others being the Fairmont Hotel magnate Benjamin Swig, Lilli Ann clothing company founder Adolph Schuman, and real estate mogul Walter Shorenstein.