The film follows Philly Wohl, Ira's mentally handicapped cousin, who at that time was 52 years old and still living with his elderly parents. Ira forces his aunt and uncle to realize that they will not be around to care for Philly forever, and that they must start making preparations for when that time should come. Philly then begins to attend classes in New York City to learn how to take care of himself and become independent.
Philly's father, Max Wohl, dies during the course of the film. His mother, Pearl, died in 1980. Philly, himself, died in late April, 2020, at the age of 92. Zero Mostel died in 1977, and the film was dedicated to his memory.
Writing in New York, David Denby called Best Boy "a remarkably powerful film" with "an undercurrent of humor".[4] In Film News, Jack Neher described Best Boy as "a beautifully detailed and very moving portrait of a family undergoing profound change".[5] In Commonweal, Colin Westerbeck wrote "It's difficult to describe the documentary that Ira Wohl has made about his cousin Philly in terms that aren't cliches. Best Boy is a movie that's "heartwarming." It's that rare film which is able to remove the quotation marks from such terms and leave us, for once, unembarrassed to use them."[6]
A sequel titled Best Man: 'Best Boy' and All of Us, 20 Years Later, was produced in 1997.[7] Following the sequel, Wohl released Best Sister in 2006, which rounded off the trilogy by looking at the effect Philly's sister had on his current life.[8]
