LOS ANGELES — Tom Bergeron, the host of the ABC reality show “Dancing With the Stars,” looked into the camera at the start of a recent Disney-themed episode and made a forceful sales pitch. Disney Plus, a new streaming service, was arriving on Nov. 12, he told the seven million people watching at home. With his voice rising, he added, “It’s available for you to pre-enroll right now!”

At that moment, Disney Plus employees, watching the live broadcast from Disney headquarters in Burbank, Calif., broke into applause. By the end of the hourlong broadcast, they had sore hands. Mr. Bergeron plugged the service over and over again.

[Watching Guide: The 50 best shows and movies to watch on Disney Plus right now.]

Anything for a corporate sibling: ABC, which is owned by Disney, has been blowing trumpets for Disney Plus as part of a kingdom-wide advertising offensive — one that Ricky Strauss, president for content and marketing at Disney Plus, has described as “a synergy campaign of a magnitude that is unprecedented in the history of the Walt Disney Company.” That is quite a statement given the gusto with which Disney typically approaches cross-promotions. But the streaming wars are escalating. Now is not the time for subtlety.

Two years ago, when Disney unveiled plans for a Netflix-style video platform, Robert A. Iger, the chief executive, made a bold proclamation: “We’re going to launch big, and we’re going to launch hot,” he said. Netflix, Amazon Prime and even a few of Disney’s traditional competitors snickered. What did Disney know about streaming and the complex technology needed to pull off that kind of service?