Hewes died Tuesday at his New York City home, his son, Tucker, said.
He joined the Saturday Review in 1951, becoming the theater critic in the mid-1950s, a position he held until the mid-1970s when he became its critic-at-large.
During his tenure at the Saturday Review, Hewes championed not only Broadway but off-Broadway, regional and international theater. He did the same while working from 1960-1964 as editor of Best Plays, a season-by-season record of theater that still is a leading theatrical reference book.
Born April 9, 1917, in Boston, Hewes graduated from Columbia University. He worked with Brooks Atkinson on the drama desk of The New York Times before going to the Saturday Review.
A board member of the American Theatre Wing, Hewes was a past member of the Tony Awards nominating and administration committees. The Wing's design award, given each year for all facets of theatrical design including sets, costumes, lighting and sound, are now called the Hewes Awards.
He was a past president of the New York Drama Critics' Circle and in 1974 he founded the American Theatre Critics Association. He was elected to the Theater Hall of Fame in 2002.
Besides his son Tucker, Hewes is survived by his wife, Jane, and two other sons, Henry and Havelock.