Gary Sladek is from North Babylon, New York. He comes from a theater family, and he has been performing acrobatic hand balancing stunts for over four decades. He has been a featured NBA Halftime Entertainer as the The Amazing Sladek. He claims to be America's Oldest Daredevil Acrobatic Hand Balancer. 
Gary's younger brother by two years, nicknamed "Broadway Jim" sometimes acts as his assistant.
Gary Sladek's audition in Episode 1102 consisted of building a stack of wooden chairs, climbing to the top of the resulting tower, and performing handstands on the top of the stack. Howie Mandel, Mel B, Heidi Klum, and Simon Cowell all voted "Yes," sending Gary to the Judge Cuts.
Gary Sladek's Judge Cuts performance in Episode 1108 consisted of performing acrobatics and comedy on a large trampoline, ending with him and Broadway Jim wearing dresses, all in a danger routine based on a criticism Heidi gave them about the outfits they wore in his first audition. Howie Mandel and Simon Cowell buzzed the act. Gary's performance was not strong enough for the judges to send him to the Quarterfinals, eliminating him from the competition instead of Deadly Games.