Trivia

One of the first films to have a pre-credits opening sequence.

Lon Chaney Jr. had played the role of "Lennie" in the Los Angeles stage production of "Of Mice and Men," and asked director Lewis Milestone for a screen test. Milestone was planning on casting Broderick Crawford in the role, but agreed to let Chaney feed lines to actresses testing for the part of "Mae." By the end of all the tests, Milestone had changed his mind, and cast Chaney in the part without a test of his own. Chaney had appeared in more than 50 films by that point in his career, but Of Mice and Men (1939) was his first major role.

Lon Chaney Jr. wore special shoes to play Lennie. These increased his height by six inches.

Lennie was Lon Chaney Jr.'s personal favorite of all his screen roles.

The movie was produced by Hal Roach, producer of Stan Laurel and Oliver Hardy and "Our Gang" comedies. During one of Roach's last interviews, television talk-show host Tom Snyder complimented him on the film. Roach responded, "It could've used more laughs."