Broadway is booming, and now more actors are going to share in the riches.

In a groundbreaking agreement Friday, the commercial producers who finance Broadway’s big hits have agreed to give a percentage of profits to performers who help develop successful shows.

The deal, reached between Actors’ Equity, a union representing 51,000 performers and stage managers, and the Broadway League, a trade organization for producers, is a milestone, marking the first time that the industry’s financiers have tacitly agreed to acknowledge that performers are contributing ideas, not just labor, to shaping new musicals and plays.

Hit shows already generate paydays for producers, directors and stars; many of them now will bring steady if modest paychecks to the supporting actors and dancers, some of whom still take survival jobs, like waiting tables, between shows.

“Creating a new show is hard,” said Mary McColl, the union’s executive director. “If we’re along for that ride at the beginning, for not much money, we think we should be able to share in the success once it has recouped its expenses.”

But actors have pointed to a practice in television and other parts of the entertainment industry — the payment of residuals for work on shows and commercials — as a precedent for compensating performers for work that leads to long-term success.

According to the union, one in four Broadway shows now puts together a developmental lab on the way to opening. There have been 75 developmental labs since 2016, about half of which led to a production, the union said.

Last month, a lack of progress on the issue prompted Equity members to strike. The strike — which did not interfere with shows already running — was the first such job action taken by Equity in nearly 50 years.

Equity unanimously approved the new agreement Friday, and gave the go-ahead for development work to start up again immediately.

The two projects that stand to benefit soonest are the jukebox musicals “Don’t Stop ‘Til You Get Enough,” about Michael Jackson, and “The Heart of Rock & Roll,” using the music of Huey Lewis and the News. Each had been planning a lab this winter.

Matt Doyle, who led a production of the Huey Lewis musical at the Old Globe in San Diego and will do the same in a New York lab later this month, said he was delighted by the agreement, both because he wants to get back to work and because he appreciates that actors are getting their due.

Mr. Doyle, who has done many staged readings and developmental labs over the years, pointed out that when actors are hired to replace cast members in a show, they are often asked to follow the outlines of the original performance.