LOS ANGELES—Last month, as the nation’s movie theaters were days from closing down, executives at Comcast Corp.’s Universal Pictures moved on a decision that would soon pay off handsomely.

A massive marketing campaign was already under way for the studio’s April 10 release, “Trolls World Tour,” an animated sequel to the 2016 hit. The studio decided not to postpone the opening, instead making the movie available as a digital rental on platforms like Apple Inc.’s Apple TV for $19.99.

Three weeks later, “Trolls World Tour” has racked up nearly $100 million in rentals.

With nearly five million rentals in the U.S. and Canada, the digital release has in three weeks generated more revenue for Universal than the original “Trolls” did during its five-month domestic theatrical run, according to a person familiar with the matter. Its performance has convinced Universal executives that digital releases can be a winning strategy, and may diminish the role of theaters even after the pandemic passes.

Hollywood has had its eye on “Trolls,” which may now offer the best ammunition yet in an industrywide push to change the way movies are released.