PARIS — The ATP, which runs the men’s professional tennis tour, has approved a large package of changes that include profit-sharing between tournaments and players and making five more of the tour’s top-line Masters 1000 events bigger and longer.

Andrea Gaudenzi, an Italian and former star player, mapped out much of this long-term plan when he applied to become chairman of the ATP, taking over the post at the beginning of 2020.

It has taken nearly two and a half years to get the package approved because of the challenges posed by the coronavirus pandemic as well as the myriad tensions and fiefs within the sport.

“This has been a long time coming, and to me, it’s a big step toward the players and the tournaments working more in alignment and more in the spirit of the partnership, which is exactly how the ATP was designed decades ago,” said Todd Martin, a former top-five singles player and ATP Player Council president who is now the chief executive of the International Tennis Hall of Fame.

The ATP is an unusual, often unwieldy partnership in professional sport between labor and management: Players and tournament owners have equal representation on the board of directors and the ability to block each other’s initiatives.

This structure has made change difficult and sometimes excruciatingly slow in a fragmented sport that also has six other governing bodies: the WTA; the International Tennis Federation; and the four Grand Slam tournaments, which operate independently from each other and the tours and generate more than 80 percent of the revenue in professional tennis.

The new ATP package, set to be announced Thursday, tries to close some of that gap by strengthening other tournaments and to close ranks within the men’s tour, which has been divided by internal dissent. Novak Djokovic, currently the No. 1 men’s singles player, spearheaded the creation of the Professional Tennis Players Association in 2020 with the goal of creating more negotiating power for the players and expanding the number of players able to earn a living on tour.

But most top men’s stars, including Rafael Nadal, Roger Federer and Andy Murray, have refused to back the P.T.P.A., and all three are part of the ATP Player Council, which was instrumental to getting the new changes approved.

It is a wide-ranging plan that also creates stricter rules on conflict of interest for board members and improving player conditions during tournaments. But the key changes come down to sharing.

The ATP will aggregate tournament rights into ATP Media, the tour’s sales, production and distribution arm. For the first time, the Masters 1000 tournaments, the nine top events on the regular men’s tour that include the Miami Open and BNP Paribas Open in Indian Wells, Calif., will share a percentage of revenue from ATP Media with the lower-category tournaments known as ATP 500s and ATP 250s. The 500s and 250s will also have guaranteed representation on an expanded board of directors.

For the first time, the Masters 1000 tournaments will allow fully independent auditing and grant the players a share of profits on top of the base prize money.

“We said, ‘Let’s start really at the root of the problem,’ which is the lack of trust between players and tournaments,” Gaudenzi said in a telephone interview. “And all those fights that every year take place and take 80 to 90 percent of our time and energy and resources and are all about 1 percent, 2 percent, 3 percent of prize money.”

Gaudenzi said the profit-sharing deal, like the ATP plan as a whole, would run for 30 years from 2023 to 2053 and called for guaranteed prize money increases of 2.5 percent each year at the Masters 1000 events. After the multilevel auditing process, players would get a percentage of profits based on their performance in all of the Masters 1000 tournaments. If the tournaments lose money, the base prize money would remain the same.

Gaudenzi said the annual bonus pool also would increase substantially, “targeting $20 million” (up from about $11 million this year), and would be paid out to 30 players instead of the current 12.

In exchange, the Masters 1000s are expanding. Until now, only Miami and Indian Wells were 12-day events with 96-player draws. But beginning next year, the tournaments in Madrid, Rome and Shanghai will expand to 11 or 12 days, and the Canadian Open and Western & Southern Open in Mason, Ohio, are set to expand in 2025.

That would leave only the Monte Carlo and Paris Masters as weeklong 1000-level events, but Gaudenzi said the hope was to expand them and make them combined men’s and women’s tournaments.

“We are trying to provide more days of premium entertainment,” Gaudenzi said.

He said market research showed that approximately one billion fans followed tennis to some degree but that the vast majority “only checks in and checks out in the big matches” like “the semifinals and finals of Slams.”

He said the goal was to create a bigger core of 100 million fans who follow the sport more closely year-round.

“The gap between the Slams and the Masters in my opinion is a little bit too great now if you compare it to, say, golf,” Gaudenzi said. “In terms of success and prize money, the majors and the PGA Tour are a lot closer, and we need to bring that level up because we want to give a narrative to fans from January to the ATP Finals at the end of the year.”

The expansion of the Masters 1000s will create fallout, reducing the available window for the smaller tournaments, particularly the ATP 250s, the lowest rung on the main tour’s ladder.

“When the schedule gets compressed, you’re going to lose some 250s somewhere,” said Bill Oakes, a former tournament director of a 250 in Winston-Salem, N.C. “People are going to be forced out, but I’ve talked to multiple tournament directors who said, ‘It’s not going to be me; it’s going to be the other guy.’”

Gaudenzi said attrition would be low but that the long-range goal was not simply to change the ATP but to grow tennis as a whole by creating more unified governance and safeguards. He added that he sought to avoid conflicts like the one this year with Wimbledon, which barred Russian and Belarusian players from playing this summer only to see the ATP and WTA retaliate by stripping the tournament of rankings points.

“It’s an unfortunate situation that causes a disruption to the players for sure and to everyone,” Gaudenzi said. “The only thing I can say is, I hope this is the last time this ever happens.”