He was the 1st to play the 'Cha-Cha Slide' on the radio. He's 'still mesmerized' by the hit.

DJ Casper, the creator of the “Cha-Cha Slide," one of the most popular line dancing songs in modern music history, died Monday at the age of 58.

The song, and its easy-to-learn dance instructions, has brought joy to countless families and friends at events of all kinds. While its words and matching moves are known far and wide, the story of how it came to be — from a catchy tune dreamed up for aerobics classes to a chance encounter with a Chicago radio DJ — is not.

From Bally's to Billboard

In the late 1990s, Casper, whose real name was Willie Perry Jr., wrote the song at the request of his nephew David Wilson, a fitness trainer who wanted something fresh to play for an aerobics class he taught at Bally's Total Fitness in Chicago's Hyde Park neighborhood, according to Billboard.

The track was initially called the "Casper Millennium Slide," later dubbed the "Casper Slide Pt. 1," and was layered over an early 1990s instrumental dance track of "Plastic Dreams" by Jaydee. It helped create a wave of excitement at Bally's and made its way to roller rinks and clubs, the Washington Post reported.

In 1999, after copyright issues, Casper mixed a new track with DJ Hudson "Hot Mix" Beauduy — this time with a live band — and called it "Casper Slide Pt. 2."

The man who put it on the airwaves

Elroy Smith, programming director of WGCI-FM, one of the Chicago’s top hip-hop and R&B radio stations, got wind of Casper's track through a colleague, the radio personality LaDonna Tittle. She had heard it making the rounds at roller rinks and aerobics classes in the city.

"When I heard it I was like, 'We gotta put this on, this is hot,'" Tittle told the Washington Post. But Smith, who prides himself in "knowing a good song when I see it," admitted he didn't think at first that the “Cha-Cha Slide" would have mainstream appeal.

"I was struggling with it. Do I play a line dance song on the radio? Like, what do I do?" Smith tells Yahoo Entertainment. "I was hesitant because I'm not thinking about dance music, I'm thinking about radio."

Smith witnessed the song's radio potential himself after going to a party and seeing the crowd's response on the dance floor. After talks with his colleagues, he decided to give the song airtime. It was the first time the "Cha-Cha Slide" had ever been played on the radio.

"We broke it at WGCI in Chicago. We were the first radio station to play it," Smith says. "That was a great feeling. What made it even more special was that it was [Casper's] hometown radio station."

Before long, the "Cha-Cha Slide" became a frequent request of listeners.

"It was on the radio for quite some time and ended up becoming part of the fabric of the station," Smith explains. "For several months we just kept it on. No one ever called to say, 'This is weird to hear a line dancing song on the radio.' To tell you the truth, I'm still mesmerized."

Michael Horton, Universal Records' vice president of urban promotion, took notice as well. In August 2000, the label released the single. As Horton told Billboard in 2003, Universal's promotional plan involved making instructional "Cha-Cha Slide" dance videos to distribute at clubs and "various Black functions, such as homecoming events at Black colleges." But it didn't come without pushback.

"Radio programmers had a strong dislike initially to the song," Horton said. "A lot of them would tell us, 'There's no way we're playing it.' But our promotion department was persistent. When radio started playing the song, we heard listeners would call stations up and ask, 'What took you so long to play this song?'"

The "Cha-Cha Slide" spent five weeks on the Billboard Hot 100 chart, peaking at No. 83. In 2004 it reached No. 1 in the United Kingdom, bumping Britney Spears from the top spot.

"People from China, people from Australia, people from Canada — it just hit all over," Tittle told the Washington Post. "It was widely embraced because everybody could dance to it — 'Everybody clap your hands' — you can hear it in a sports stadium."

"A good song will rise to the top," Smith says. "There are adults that love to do this type of dance, and there has not been a new line dance song that’s become as popular as the 'Cha-Cha Slide.'"

Roughly 23 years later, he says it's "nearly impossible" to attend large family gatherings or celebratory events without a DJ playing the tune. "And if they don't, it will get requested."

The song's legacy endures

Casper understood the song's unique appeal across generations.

"It was something that everybody could do," he told Chicago news station WLS-TV in May. "I have one of the biggest songs that is played at all stadiums: hockey, basketball, football, baseball. They played it at the Olympics."

In a 2012 interview with The DJ Podcast, Casper explained that the point of the song was to get people moving. "All of the slides and the line dances are pretty much for exercising,” he said. "They make you move, for cardiac, you know, for your heart. It keeps you motivated."

As for Smith, who began a friendship with Casper over the years, he says the DJ never forgot where he came from, and always gave credit back to WGCI-FM, as well as the people of Chicago, who helped the song reach new heights. Specifically, the Black and brown community, who've embraced it "almost like an anthem."

That, Smith says, is perhaps Casper's greatest legacy.

"The song unifies cultures. It's as simple as that," he says. “Black and brown culture, we love to celebrate, we love to have fun and we love to be unified. When that song comes on, it's gonna make you feel good."