Reid, 55, a married father of four, is the former chairman of Island Def Jam Music Group and current chairman and CEO of Sony's Epic Label Group. He was a key player in the monster successes of Kanye West, Mariah Carey, Rihanna, Bon Jovi and Justin Bieber, among others. His eye for talent is legendary – he signed a 14-year-old Usher to his old label, LaFace Records. He's also produced and written a slew of R&B hits, including more than 30 No. 1 singles.
No wonder Reid doesn't flinch at being a rookie reality-TV judge. "I have never watched any singing competition," he tells PEOPLE. "But I have judged talent my whole life. I just didn't do it on television. It's what I do, who I am." Adds Cowell: "He's the guy all the contestants want to impress because of his track record."
Here are five more tidbits about music TV's man of the moment:
1. He's Competitive with Simon
"If someone auditions and I say no and Simon says yes … or if I say yes and he says no, I want to see how far they get, because I want to see who is most accurate from the very first time we watched them," Reid tells PEOPLE. The friendly rivalry goes beyond the camera, too. "It started on the first day of filming, when they started checking out which car the other arrived in. They are just like two schoolboys," an insider tells PEOPLE. For example, if Cowell arrives in a sedan, Reid will request an SUV. If Simon's car has large tires, Reid's car will have even bigger tires.
2. He Has a Taste for the Finer Things
Reid plans to ship his entire New York office to Los Angeles, where he'll be based now, says the insider, adding that Reid has requested that it include a fully stocked wine cellar, 5-ft.-tall speaker sets to play his music, and a special "cooled" area to store his most exquisite cigars.
3. He and Babyface Go Way Back
The pair played in '80s R&B band Deele and had a hit in 1988 with "The Two Occasions." Later, they formed a label, LaFace, in a joint venture with Arista Records and Clive Davis. Reid went on to sign 14-year-old Usher Raymond, who later dropped his last name and became simply Usher. The pair also worked with Reid's future fellow X Factor judge Paula Abdul. "L.A. [co-wrote] my first hit, 'Knocked Out.' I got L.A. and Babyface their first publishing deal at Virgin Records," says Abdul. (Daryl Simmons is also credited with writing the song with Reid and Babyface.)
4. He Was Married to '80s Pop Singer Pebbles
Reid and Perri "Pebbles" Reid wed in 1989 and remained together seven years. They raised Perri's daughter Ashley and had two boys of their own, Antonio Jr. and Aaron. Reid then married former schoolteacher Erica Holton in 2000. They have a son, Addison Kennedy, and a daughter, Arriana Manuelle.
5. He's a Fitness Buff and a Picky Eater
"He is a health-food nut, I'm always trying to get him to eat," says Nicole Scherzinger, another X Factor judge. As for the nickname L.A.? He got it when he was a young musician for having the nerve to wear an "L.A." T-shirt in Cincinnati during a heated playoff series between his hometown Reds and the Los Angeles Dodgers.