Mariah Carey's Christmases are merrier than ever since she debuted 'All I Want for Christmas Is You.' How she turned the song into an empire.

To understand just how big of a song Mariah Carey's "All I Want for Christmas Is You" is, even if you've never heard it — can you even remember when that was the case? — you really only need to know one thing: In April, it was added to the Library of Congress' National Recording Registry.

Like standards such as Bing Crosby's "White Christmas" and Nat King Cole's "The Christmas Song," as well as non-holiday fare like Aretha Franklin's "Respect" and President Franklin D. Roosevelt's "Fireside Chats," "All I Want for Christmas Is You" is one of just 625 titles that have been selected as worth preserving for future generations," because it's "culturally, historically or aesthetically significant."

Released in November 1994 as a single from Carey's fourth album, Merry Christmas, "All I Want for Christmas" is infectious, with relatable lyrics and a tune reminiscent of a Darlene Love recording. It was a hit from the start... and the next year and the next.

"You could argue that 'All I Want for Christmas Is You' is Mariah's most impactful and everlasting song," Dan Enriquez, one of the hosts of The Mariah Report Podcast, tells Yahoo Entertainment. "I love the fact that Mariah has really leaned into the public's love for the song. Every year she brings new life to it, whether it's in a collaboration with McDonald's, remixes, new holiday merchandise or her annual holiday concerts, she is the 'Queen of Christmas'!"

All of this is to say that, over time, Carey's song seeped into our cultural consciousness, as she performed it at the Christmas tree lighting at Rockefeller Center in New York City, Christmas in Washington, Walt Disney World's Christmas Day parade and elsewhere. It's become part of her brand. Every year, as soon as Halloween is over, Carey joins retail stores in declaring it the holiday season. The key phrase being as soon as.

In 2023, on Nov. 1, she dropped a video that showed her frozen in ice, being thawed out by pumpkins and ghouls at the precise moment that the clock switches over from October. "It's tiiiiime!" she belts out in one of her signature high notes, shattering the ice and cueing the first notes of what's become her signature song.

And it's not by accident, darling. As Carey herself told Yahoo Entertainment in 2019, Christmas is "my entire focus of my year."

A streaming smash

The Christmas bop is in regular rotation on radio stations that go all-holiday in the weeks and months before Dec. 25. At the same time, Carey's song sees a bump in streaming — where it really doesn't need any help.

The ditty ranked No. 1 on the list of the Greatest of All Time Holiday 100 Songs compiled in 2021 by music chart-makers Billboard, where it left songs such as "Rockin' Around the Christmas Tree" and "Jingle Bell Rock" in the dust snow. The rankings were based on a combination of streaming data, sales and radio airplay.

Last year alone, the Christmas track became the first song ever to have topped Billboard's weekly Top 100 chart four separate times, from 2019 to 2022. By the time we were stuffing used wrapping paper into a trash bag on Dec. 27, Vulture reported that Carey had (again) broken the record for the most single-day streams on Spotify's global chart, having been played a staggering 21.273 million times on Dec. 24.

None of this includes the various versions of the song Carey created. For instance, she released one with Justin Bieber, "All I Want for Christmas Is You (SuperFestive!)" in 2011, and 2020's "Magical Christmas Mix."

Jay Towers is an anchor on Fox affiliate WJBK in Detroit and a host of iHeartRadio's WNIC, which switches over to holiday music very early. It's Nov. 3 this year. He tells Yahoo Entertainment in an email that he loves the song, but…

"I'm good with tucking it away at the end of December," Tower says.

He explains that it's in high demand during the season.

"I've been hosting a Top 30 Holiday Countdown that airs on iHeartRadio Christmas stations across America for the past 13 years," he says. "I've observed 'All I Want for Christmas Is You' consistently ranking in the top three, if not claiming the No. 1 spot year after year. It consistently outperforms even the most nostalgic Christmas classics."

Seasonal fare on the screen... and on the racks

Carey's song isn't just on the radio and streamers. It's live on her festive and lucrative holiday tours and beyond.

As fans of romantic comedies know, it plays a key part in the 2003 holiday classic Love Actually. "All I Want for Christmas Is You," the standout number at a school talent show in the big finale, is part of the soundtrack, although it's performed by Olivia Olson, the actress who sings it in the movie, rather than Carey. Still, it sends Love Actually viewers pulling looking for Carey's version when they see the film.

Enriquez credits the heartwarming film with giving people who hadn't been part of Carey's "Lambily," as her fans are known, a reason to love it, too. He explains that "in the last decade or so, the song really started making an impact with the help of streaming, YouTube and social media."

While Enriquez, who knows Carey's entire catalog well, prefers the artist's other songs over "All I Want For Christmas Is You," he understands why it's a favorite for some.

"She wasn't trying to make a modern Christmas classic," Enriquez says. "She was simply putting her true love of Christmas into a song and it's that genuine love that people connect with when they hear the song every year. I love the song because of the joy it brings people every holiday season, including Mariah herself."

Carey has reportedly said that the single was created out of "the need for me to express myself and make a song that made me feel happy at the holidays."

The catchy tune found other fans on soundtracks for Glee and Disney, as it became part of the cultural fabric.

As Towers sees it, the song has "become a defining moment in pop culture, almost marking the official start of the holiday season" — a season filled with Carey.

She created specials around her persona as a glamorous elf, then a children's picture book. In 2017, Henry Winkler, Lacey Chabert and Carey herself loaned their voices to a direct-to-video movie based on it.

Beyond that, the perennial success of Carey's song has spawned an unfathomable amount of branded stuff. An entire section of her website is now dedicated to "It's Time" merch: pajamas, aprons, ornaments, blankets and more.

The (financial) bottom line

Despite all this, Carey's application to trademark the phrases "Queen of Christmas," "QOC" and "Princess of Christmas" was denied in 2022. Another singer, Elizabeth Chan, who is a full-time Christmas recording artist, challenged it. She said that the holiday shouldn't belong to any one person.

"It's the erasing of anybody else except for one person. The consequences were really, really serious," Chan told Yahoo in 2022. "I had to be brave enough to stand up."

Love spoke out, too, noting that she had been given the title during her annual performance of "Christmas (Baby Please Come Home)" on David Letterman's late-night talk show.

Carey's faced legal woes, too, including charges of copyright infringement from songwriter Andy Stone, who performs as Vince Vance. He claimed in a 2022 filing that his group, Vince Vance and the Valiants, released a song very similar to "All I Want for Christmas Is You" in 1989, five years before Carey's "derivative version." He dropped the lawsuit later that year but refiled it with more detail just this week.

So far, none of this has cut into the singer's haul from the song she co-wrote with Walter Afanasieff. The Economist estimated in 2017 that "All I Want" had generated more than $60 million, and that was six years ago. According to a 2022 Billboard report, she earns about $1.55 million in royalties each year.

This year, her "Merry Christmas One and All!" tour kicks off Nov. 15 and stops at more than a dozen cities before winding down at New York City's Madison Square Garden on Dec. 17.