Technically "younger," Roy was born half an hour after John. The twins debuted in Anthony Asquith's 1931 film Tell England at eighteen while attending Berkshire's Reading School. Roy spent a few years in Canada, returning home around 1933. Following Roy's debut as an assistant director on Apron Fools comedy quickie in 1936, the brothers established Charter Film Productions and began making shorts. Boultings came to prominence in 1940 with Pastor Hall, Martin Niemöller's anti-nazi biopic based on Ernst Toller's eponymous play. During the Second World War, Roy made several military documentaries with the Army Film Unit, including Desert Victory (1941), which earned him the Academy Award. The brothers co-produced and co-directed several movies, including the Golden Lion-nominee thriller Seven Days to Noon in 1950. Roy also made a few Hollywood movies independently from John, starting with the WWII naval epic Sailor of the King with [url=https://discogs.com/artist/8239264]Jeffrey Hunter[/url], produced in 1953 for [l=20th Century Fox]. Between 1956 and 1959, they filmed a series of critically acclaimed satirical comedies with a star cast of Richard Attenborough, Terry-Thomas, [url=https://discogs.com/artist/791410]Ian Carmichael[/url], and Peter Sellers.

In 1966, Roy directed The Family Way, a well-accepted comedy starring [url=https://discogs.com/artist/1390467]John Mills[/url] and his 20-year-old daughter, a former [l=Walt Disney] child star Hayley Mills; Roy began dating Hayley, who was 33 years younger, right on the movie set. Roy's next movie in 1968, psychological thriller Twisted Nerve starring Hywel Bennett, Billie Whitelaw, and Frank Finlay and produced by [a=George W. George]/Frank Granat duo, caused a notable controversy as it essentially implied that people with Down syndrome (still known as "mongoloids") are prone to violence and crime. The National Association for Mental Health and [a=David Ennals], then Minister for the State of Health, sent complaints to BBFC (British Board of Film Censors); Twisted Nerve's medical adviser, renowned psychiatrist [a=Lionel Penrose], asked to remove his name from the credits. Shocked and upset, Roy Boulting added an opening disclaimer trying to backpedal on the film's message, which only fueled more criticism in the British press. (Since John was merely an executive producer, all uproar fell on Roy, whose reputation was already somewhat tamed as he continued publicly dating Hayley Mills, yet they weren't married.)

In 1970, Roy bounced back with There's a Girl in My Soup romantic comedy, co-produced by John with M. J. Frankovich and starring Peter Sellers and Goldie Hawn; it became their last notable success. The following comedy, Soft Beds, Hard Battles, became a massive commercial flop despite a prominent cast of Sellers, Curd Jürgens, Lila Kedrova, and Jenny Hanley, and caused Roy significant financial losses; it was John's last job in Hollywood. Roy directed one more comedy in 1979, The Last Word, which saw only limited release and performed even worse in the UK's box office. After John died of cancer in 1985, he stopped making films.