Curious, I did a quick search online and read a bit more about him. As Mary points out in her comment, he operated in New York City for decades and last operated out of a Midtown shop on 53rd St. Benham seemed to attract clientele from the performing arts, movies and entertainment. You can see him standing on the left in the photo above dated 1937, wearing presumably one of his own creations - a fairly trim jacket with full cut trousers and slightly extended shoulders.
Above is a photo from the auction house Heritage Auctions featuring items of the 1950s comedian Ernie Kovacs. Among items from Benham, Kovacs also owned tailored items from the Savile Row tailor Dege (prior to merging with Skinner) and L.R. Ermilio of Philadelphia. Another customer was the classical music conductor Alfred Wallenstein, whose bill from Benham can be seen (purchased if you're so inclined).