It was unusual back in 2001: a musical arriving on Broadway with a predominantly female leadership team, from the show’s top producer to its director to its book writer.

It’s still pretty rare. This year’s Tony Awards champ, “Fun Home,” marked the very first time the trophy for best score had gone to an all-female songwriting duo (Jeanine Tesori and Lisa Kron). Two of the show’s three lead commercial producers are women (Kristin Caskey and Barbara Whitman), which is also still uncommon on Broadway, where male producers far outnumber women in the game.

From the perspective of nearly 15 years later, that 2001 production stands as something of a landmark — in more ways than one. Because that show was “Mamma Mia!,” the Abba musical that became one of the elite musical-theater titles to join the pantheon of worldwide smash hits alongside “The Phantom of the Opera,” “The Lion King” and “Wicked.” Its 2008 movie adaptation is the most successful live-action movie musical in history.

With Hollywood currently struggling with issues of gender parity, and female playwrights calling for greater representation in theater programming, “Mamma Mia!” — which closes in New York Sept. 12 as the eighth longest-running Broadway musical of all time — serves as an early milestone.

Not that any of that was on producer Judy Craymer’s radar back then. “There wasn’t a feminist approach to it. I just wanted to get the project on,” she said. “Having a team of women was serendipitous, because it instinctively worked with the piece. But there was also an element of: All the men had said no.”

In her struggle to launch the show on the West End — famously selling her home to bankroll the project — she enlisted director Phyllida Lloyd, who had directed plays and operas but never a commercial musical, and playwright Catherine Johnson (“Rag Doll,” “Too Much Too Young”) to concoct an original story from the hits of Abba, penned by Bjorn Ulvaeus and Benny Andersson (both of whom were also involved with development of the show from the get-go).

The crowd-pleasing tale that the creatives came up with, set on a sunny Greek isle, centers on a mother, a daughter, an impending marriage and the three men who might be the younger woman’s father. Even that fizzy storyline has a subtly feminist undercurrent, in that the musical nonjudgmentally allows lead character Donna Sheridan (initially played by Louise Pitre on Broadway, and by Meryl Streep in the movie) to have the kind of wild-oats-sowing youth that men get to have in fiction all the time.

The audience appeal of the musical was further broadened by a welcoming vibe that was central to Lloyd’s conception for the show. “When we were first casting, we had to say it, and say it again, that we were looking for people who were as imperfect as we were,” said Lloyd (“The Iron Lady”), who also directed the film version of “Mamma Mia!” “It was all about that warts-and-all look on the stage. You didn’t have to be a size zero, for instance. You don’t have to look a certain way to get in.”

The musical also created plum roles for an age range that doesn’t often get them on Broadway. “It’s a show with very strong roles for women who are middle-aged and, dare I say, middle-age-plus,” Craymer noted. “There are six great roles there for middle-aged women and men.” In another boost to the musical’s selling power, the age bracket of those characters smartly aligns with the predominantly older, mostly female ticket buyers who account for the bulk of all Broadway sales.

When the production opened in 1999 in London, where the show is still running, “Mamma Mia!” surprised the West End with the magnitude of its success and the fervor of its audiences’ enthusiasm. Broadway types smelled a transatlantic hit, but the show took the roundabout route to New York.

The flop of their 1986 musical “Chess” was said to have made Ulvaeus and Andersson think Abba tunes wouldn’t sell in America, so Craymer and company dipped a toe in the North American market with a Toronto production ahead of a tour. The Canadian staging sold so well that producers kept it there, and had to scramble to pull together a separate production for the road.

That tour was still going when “Mamma Mia!” opened on Broadway. That’s a flip of the conventional wisdom that holds that a production should launch in New York before carrying its Broadway imprimatur to the regions.

The strategy worked. “Mamma Mia!” began Broadway previews Oct. 5, 2001, with $27 million in advance sales in the bank. “The tour acted liked a big national commercial,” said Nina Lannan, the show’s general manager. Earning surprisingly upbeat reviews for a frothy entertainment, “Mamma Mia!” cheered a city still reeling from the attacks of Sept. 11 and became one of Broadway’s top sellers.

When “Mamma Mia!” closes, the New York production alone will have grossed about $625 million. Its success spawned a string of copycat musicals attempting to cash in on a hit song catalog, many of which (“Good Vibrations,” “Lennon”) tanked.

Having played 49 productions in more than 400 cities around the world (including a five-year run in Vegas, which had been considered a notoriously difficult musical-theater market), “Mamma Mia!” has racked up a worldwide gross topping $2 billion. Not many musicals hit those heights — and never before had that kind of a blockbuster been launched by a predominantly female team.

“We were always aware it was these three women who pushed this show forward, and that was rare,” Lannan remembered.

Box office for the Broadway stage began to slow in recent years, but the musical’s still going in London and will launch its first U.K. tour later this year. There’s also a cruise-ship production running on one of Royal Caribbean’s ships.

The timing of the Broadway staging’s closing notice, which went up in April, spurred sales all throughout the summer, helping “Mamma Mia!” to go out with a bang. But don’t look for a lavish blowout on the last night itself.

“There’s nothing huge planned, really,” Craymer said. “Apart from tears and a lot of vodka.”