It can’t rightly be called a commercial, because in 1939 television was experimental, but on Saturday, September 2nd, 1939 station W2XBS in New York City may have broadcast the very first televised movie trailer. The NBC station, which began regularly scheduled broadcasts on April 30th of that year, aired scenes from Golden Boy, produced by Columbia Pictures, at 9:15PM. The New York Times reported on the broadcast:
While full-length current motion pictures are withheld from television by the producers to protect the box-office, televiewers may at least catch occasional glimpses of Hollywood stars as trailers are telecast. Recognizing the publicity value of trailer-telecasts, Columbia Pictures has granted permission to show samples of pictures, according to the National Broadcasting Company. Scenes from “Golden Boy,” scheduled for release in September, have been selected to test the possibilties in such telecasting on Saturday night at 8:15 o’clock.
Television listings in The New York Times show a program called “Twinkletoes” by Ned Wayburn and a “film preview” of Golden Boy airing during the 9-9:30PM half-hour. Golden Boy, starring Barbara Stanwyck, Adolphe Menjou, William Holden and Lee J. Cobb, was released on September 5th, 1939. There’s no way of knowing if the film, which was based on a play by Clifford Odets, benefited from the W2XBS broadcast.
Although the brief article in The New York Times suggests that additional trailers would be broadcast I haven’t been able to find evidence of any others.
“Televiews of Pictures.” New York Times. 27 Aug. 1939: X10.