The blind, autistic 22-year-old singer and pianist was introduced to the audience through a powerful pre-taped package that followed his adoring mom, Tina Lee, as she explained how she first found out her son was blind when he was only three months old, and soon after doctors delivered another diagnosis.
"They said, we think he may have autism. And I didn't know what to do," Tina shared in the package, adding that they came to a breakthrough when she discovered that Kodi loved music. "That's what happened. It was the hope. It was something of his own that gave him joy. And I was like, 'Now I know how to help you, as your mom.'"
"With all of the hardships that he's had, he taught me that anything is possible," Tina added, close to crying. "Kodi finally gets to show the whole world who he is."
Before he began his performance, Kodi sat at his piano while his mom kneeled beside him, giving him a pep-talk and psyching him up for his big number. After giving him a loving smile, Tina walked off into the wings and Kodi began to play.
For his first performance since getting the Golden Buzzer, Kodi gave a soulful, virtuosic rendition of the iconic Simon and Garfunkel tune, "Bridge Over Troubled Waters," that brought tears to everyone's eyes.
As host Terry Crews stood with Kodi's mom by the side of the stage, he clearly tried to choke back tears as he watched the moving, impassioned performance -- and the judges were equally affected by the gorgeous number.
His stunning performance was met with an overwhelming standing ovation from everyone, including all four judges.
Gabrielle Union -- who was the one to award Kodi the Golden Buzzer over 10 weeks ago -- was the first to address Kodi and was overcome with emotion.
"Who you are and what you stand for and what you continued to do makes the world such a better and so much more of a beautiful place," Gabrielle said as she fought back tears of her own. "We have to stop putting limits on our children. We have to keep believing in each other. Thank you for letting me be a part of your journey."
Simon Cowell was equally effusive with his praise, telling Kodi, "You continually amaze me."
Simon also extended a special thank you to the legendary Paul Simon, the writer of the classic song Kodi covered, who "never really gives permission to anyone to sing this song because it's very precious to him."
"But he gave clearance within 30 minutes because he saw you're audition," Simon added, before expressing that Kodi is "genuinely one of the most extraordinary people and talents we've had the great fortune to have on any show we've ever made."
Finally, Kodi got a chance to address his millions of fans, saying excitedly, "Thank you for all of your support and I love you all!"
Kodi and Tina spoke with ET's Keltie Knight after the show, and the proud mom said that the support and love from the judges and the audience is more special than she could ever explain.
"He has been working his butt off to get here and he's worked so hard," Tina shared. "This is what he's always wanted to do. He's wanted to perform in front of thousands of people and this is in front of millions of people!"
As for what goal Kodi has set his sights on next, the 22-year-old singer said he's hoping to get the chance to one day perform at the GRAMMYs.
ET also spoke with judges Howie and Gabrielle who both pointed to Kodi when it came to who they thought might be this season's frontrunner.
"I think it's a no brainer: Kodi Lee. I mean, he already has almost half a billion views online from his audition and his Golden Buzzer moment [and tonight] I think he beat that moment," Howie marveled.
As for Gabrielle, she admitted that she is "a little biased" because she was the only who gave him the Golden Buzzer in the first place, but said that Kodi is "a world changing, culture shifting, once in a lifetime talent."
"I think his audition being viewed almost half a billion times is a testament to his power [and] how thirsty we are as a people to watch what we think might be impossible become possible," she added.
Terry also chimed in on Kodi's standout performance and told us he's " still emotional" after watching it.
Meanwhile, fans can vote for Kodi now and America will see if the talented performer will be moving on to the semi-finals during the America's Got Talent results show, which kicks off on Wednesday at 8 p.m. ET/PT on NBC.