Hemion began working in live television in New York in the 1950s, particularly for the original Tonight Show starring Steve Allen. In the 1960s, Hemion began concentrating on musical-variety shows, working with producer Gary Smith on a popular series of Kraft Music Hall specials for NBC-TV. Smith-Hemion Productions arguably defined the fast-paced look and glamorous style of the American comedy-variety genre, and influenced scores of later generations working in television.
Hemion had a knack for balancing both visual and musical elements that made him a master of directing concert performance specials. He worked with such major stars as Frank Sinatra, Barbra Streisand, Paul McCartney, Bette Midler, Shirley MacLaine, Julie Andrews, Elvis Presley, Burt Bacharach, The Muppets, and Luciano Pavarotti. He also won Emmys for directing the Kennedy Center Honors in 1989 and 1990.
Among the most memorable specials that Hemion produced and directed were: My Name Is Barbra (1965), Frank Sinatra: A Man and His Music (1965), Peter Pan (a quickly forgotten 1976 version with a new score, not to be confused with the classic musical starring Mary Martin), Baryshnikov on Broadway (1980), and Barbra Streisand: The Concert (1994). Along with producing partner Gary Smith, Hemion later branched out into producing large conventions, including the nomination conventions for the Democratic National Party as well as the inaugural ceremonies for Ronald Reagan and Bill Clinton.
Hemion died of kidney failure, at the age of 81.