His most prominent TV roles were Detective Brennan in My Favorite Martian and the district attorney in How to Murder Your Wife.

[2] His obituary in The New York Times noted that he "scored his biggest successes on Broadway in William Saroyan's Love's Old Sweet Song and John Steinbeck's The Moon Is Down.

[4] Among the movies Hewitt appeared in are A Private's Affair, That Touch of Mink, Days of Wine and Roses, Follow That Dream, How to Murder Your Wife, Sweet Charity, and The Barefoot Executive.

[2] An obituary noted, "He helped to establish the employment survey for performers in the American theater and frequently wrote letters and articles about actors' rights as professionals.

The material housed at the Dartmouth College Library includes "programs, scripts, clippings, sides, reviews, correspondence, playbills, photographs and tapes."