Richard Pryor may have saved “National Lampoon’s Animal House.”

In 1978, Universal’s film division president, Ned Tanen, was in a rage about the not-yet-released Kennedy-era comedy. He was particularly livid over a scene in which white fraternity brothers and their sorority dates feel threatened by a roadhouse full of African-Americans. “Ned said, ‘You have to cut the whole black bar scene. There will be riots across America,’” the director John Landis recalled in a recent interview.

A young Universal executive championed the film and screened it for the legendary comedian. “He sent Ned a note on paper that said at the top, ‘From the desk of Richard Pryor,’ and he wrote: ‘Ned, ‘Animal House’ is [expletive] funny, and white people are crazy,’” Mr. Landis remembered with a laugh. “It was like a papal blessing.”

“Animal House,” which was made for $2.1 million, went on to gross $141.6 million domestically after its release on July 28, 1978. Nearly 40 years later, we caught up with many of the cast members including Kevin Bacon (who made his film debut in the comedy) and Donald Sutherland, along with Mr. Landis and the producer Ivan Reitman to tell the back story of the quintessential summer comedy.

They recalled the film’s breakout star, John Belushi, who died of a drug overdose in 1982 at 33, as well as a real food fight and an on-campus melee.