Mike had competed on Season 17 of America's Got Talent. While he finished as a finalist, he was cut before the Top 5.
"The way I got sent home, it actually pushed me to work harder," Mike said in a video package that aired before his comedy routine.
"Ever since I left America's Got talent, it's been nothing but star-studded life experience. I've been working nonstop."
In fact, America's Got Talent: All-Stars judge and comedian Howie Mandel had invited Mike on Season 17 to open up one of his comedy shows, but Mike revealed on Monday that he hasn't had the time to do so yet because he's been so busy.
Mike said he thought he came up with "the funniest set ever" to perform on the America's Got Talent: All-Stars stage.
"There's a lot of people that say winning is making it to the finals, but I'm not one of those. I'm going to take everybody out by every means necessary," Mike joked backstage.
When Mike told the audience jokes about his family life, he had the crowd and the judging panel -- also comprised of model Heidi Klum -- cracking up.
"I love you," Heidi told Mike once he was finished with his routine. "You do have that superstar smile and you are a ray of sunshine. I love you and you are hilarious."
Simon then gushed, "If you had done that routine in the finals [last season], it might have been a completely different story because you've come back funnier, more confident."
"I can even see it in your eyes how much this means to you right now," Simon added.
Mike responded to the judge, "It means everything... This is what I've wanted forever. I've been doing this for almost 20 years and when you finally get a platform, there's no time to take off or put on brakes. I'm here to play!"
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Simon, seemingly impressed by Mike's drive and passion for his craft, then announced, "You know what, Mike? I love, love, love people who compete. And I wasn't expecting to do this, but I'm going to do it."
Simon proceeded to hit his Golden Buzzer and then join Mike onstage for a hug. Simon told Mike face-to-face how his routine was "really funny" and the crowd really liked him.
"I'm trying to hold it back, man, but this is the dream! This is the dream!" Mike exclaimed.
Saxophonist Avery Dixon, who also previously competed on America's Got Talent's seventeenth season, won the SuperFan Vote and will therefore also be competing in the finale.
Mentalist or psychic Peter Antoniou, who initially competed on America's Got Talent's sixteenth season, finished the live SuperFan Vote in second place.
Singer Keren Montero, the former winner of Dominicana's Got Talent, placed third in the night's voting results.
Mike and Avery will join self-taught aerialist Aidan Bryant, the Detroit Youth Choir, dance group Light Balance Kids, and hand-balancing act the Bello Sisters as finalists on America's Got Talent: All-Stars this season.
Detroit Youth Choir had received Terry's Golden Buzzer last week, and the week before that, Howie pressed the Golden Buzzer for Light Balance Kids.