Simon Cowell has been in the entertainment business for a long, long time. He's made a name for himself as one of the toughest judges, and has been a producer of and judge for some of the biggest talent competition shows in the world. This includes American Idol, Pop Idol, The X Factor UK, The X Factory U.S., Britain's Got Talent, America's Got Talent, and more. While Simon is known for his insults and blunt comments about contestants, the man has a good eye for talent.In fact, he's discovered a large variety of musicians in his time. As founder and CEO of Syco Entertainment, Simon has worked hard to find the best talent all around the world. Want to know more? Let's go.Who has Simon Cowell discovered?Some of the biggest starts Simon Cowell has discovered include: Leona Lewis (The X Factor), Fifth Harmony (The X Factor), Noah Cyrus (who was not discovered on a talent show), Susan Boyle (Britain’s Got Talent), Sinitta (Simon signed her with his first pop label Fanfare Records), One Direction (The X Factor), Jackie Evancho (AGT), Little Mix (The X Factor), James Arthur (The X Factor), Labrinth (Labrinth hadn't been on any talent shows), Grace VanderWaal (AGT), and Cher Loyd (The X Factor).Simon founded several labels through the years. Fanfare Records was his first, which he started in the '80s. His official first single was Sinitta’s "So Macho" in 1986. Then, in the early '90s, he started a new label called S Records, and signed with acts like the Power Rangers (yes really) and the puppets Zig and Zag (we all have to start somewhere). Then, in 1995, he signed the actors Robson Green and Jerome Flynn.He then created his first talent TV show called Pop Idol, based in the U.K. and later produced the U.S. counterpart, American Idol, which premiered in 2002. In conjunction, he started his new company Syco, which branched out into music, TV, and film. Syco later produced The X Factor and then America's Got Talent.So...how did Simon get here? His ambition. “Simon is the opposite of complacent. He has ambition. He’s not afraid to push boundaries. He’s not afraid to fight for what he believes creatively, and he wants to lead the way. He’s always thinking, ‘How do I make it better? What’s next? What do we need to do on Got Talent next year to stay ahead of the game?’ He never, ever rests on his laurels. Ever," says Cecile Frot-Coutaz, the former CEO of FremantleMedia, and someone who's worked closely with him.“When he’s sitting at the judging table, he’s not just there as an artist who knows what sounds right, what doesn’t sound right. He’s also somebody who understands how to produce an album, but also how to produce television. So he produces himself, and he produces the panel as he’s sitting at the desk," Cecile told Variety in 2018.What's his secret? “It’s harder than people think, because you’ve got to be able to spot something in somebody in three minutes, and make a decision that that person could become a star," Simon says.Has Simon Cowell ever signed someone from 'AGT'?While most of Simon Cowell's discoveries have been from The X Factor, he did sign Grace VanderWaal, Jackie Evancho, and Courtney Hadwin from America's Got Talent.Watch the latest season of AGT every Tuesday night at 8 p.m. EST on NBC.