Twenty years ago, Juvenile asked the world to “Back That Azz Up,” and the world obliged.

That smash single from Juvenile’s multimillion-selling 1998 album “400 Degreez” established New Orleans hip-hop as a commercial force and introduced the local "bounce" sound to the nation. It also filled the coffers of Cash Money Records with enough cash money to buy all the Bentleys and helicopters the most garish of rap videos required.

Juvenile has commemorated the 20th anniversary of “400 Degreez” throughout the year. The celebration culminates on Saturday at the Joy Theater. In addition to Juvenile, the bill includes Whop Bezzy, Jay Lewis and Partners-N-Crime. Show time is 9 p.m.; tickets start at $25.

Born Terius Gray, Juvenile spent part of his youth living in the Magnolia housing development. He was on the scene as bounce, with its singsong melodies, call-and-response choruses and infectious beats, took root at block parties and dances. He first achieved local notoriety with his featured rap on DJ Jimi’s “Bounce (For the Juvenile).”

He came into his own after joining the roster of Cash Money Records. Founded in New Orleans in the early 1990s by brothers Ronald “Slim” Williams and Bryan “Birdman” “Baby” Williams, Cash Money was already making money before “400 Degreez.” The label steadily churned out regional hits by B.G., Magnolia Shorty, U.N.L.V. and the Hot Boys, the all-star quartet featuring Juvenile, B.G., Turk and a largely unknown teenager called Lil Wayne.

But “400 Degreez” changed everything.

Released on Nov. 3, 1998, via Cash Money’s new distribution deal with major label Universal Records, “400 Degreez” was Juvenile’s third solo album, but far and away his most commercial.

Producer Mannie Fresh, the architect of Cash Money’s classic sound, blended fat-bottomed beats and live instruments in a way that nodded to Juvenile’s New Orleans pedigree but was also palatable to a national audience. Spoken-word skits between the songs added a touch of humor and made the record seem all the more real.

The single “Ha” hit No. 68 on the Billboard Hot 100 chart and was widely hailed as one of the year’s best singles. But “Back That Azz Up” — or, in its sanitized form, “Back That Thang Up” — blew up as a cultural phenomenon.

The video, shot on location in the Magnolia housing development, offered a firsthand look at New Orleans hip-hop culture. Numerous women demonstrate the aerobic gyration requested in the song’s title, twerking before the term had even entered the lexicon.

juvenile 400 degreez

New Orleans rapper Juvenile's 1998 album '400 Degreez' sold more than 4 million copies.

Powered by the success of “Ha” and “Back That Azz Up,” “400 Degreez” sold 4 million copies — an enormous number, even for the days when music consumers still bought albums. “400 Degreez” was not only the best-selling rap album of 1998, but, 20 years later, it remains the top seller in the entire Cash Money catalog. It even outperformed Lil Wayne’s landmark, much acclaimed “Tha Carter III,” which was released a decade later. “400 Degreez” may well be the best-selling album by any New Orleans artist of the past 50 years.

As was perhaps inevitable, “400 Degreez” proved to be Juvenile’s commercial peak. His follow-up, 1999’s “Tha G-Code,” sold “only” a million copies. His next release, “Project English,” only managed to go gold. He returned to platinum status with 2003’s “Juve the Great,” thanks to the No. 1 single “Slow Motion,” featuring recently deceased New Orleans gangsta rapper Soulja Slim.

Juvenile subsequently parted ways with Cash Money; like some other acts on the label, he alleged that he was cheated out of royalties. He left for Atlantic Records, but was never able to replicate his early success.

In recent years, a smattering of arrests — nightclub fights, failure to pay child support, etc. — have generated more headlines than his new music. He lost a home in Slidell to Hurricane Katrina’s storm surge; his “Get Ya Hustle On” recounted the post-hurricane hustle in which many locals engaged.

But “Get Ya Hustle On” was not the cultural force that “Back That Azz Up” was. Juvenile defended his most famous and lucrative song in court. In one of the more colorful cases to cross the federal docket, local bounce music pioneer Jerome “DJ Jubilee” Temple sued Juvenile, alleging that “Back That Azz Up” infringed on the copyright of Temple’s similar “Back that Ass Up.” In 2003, a jury sided with Juvenile, an outcome later upheld by the 5th Circuit Court of Appeals.

And so Juvenile is free to “Back That Azz Up” forever.

Follow Keith Spera on Twitter, @KeithSpera.

Keith Spera writes about music, culture and his kids.