Before taking the stage, Williams -- who is one of 10 hopefuls who got one last chance to impress the country on Tuesday -- shared a letter he received from a man named Ronnie Long, whose story resembles Williams' own.
In a pre-taped segment that aired before his performance, Williams shared an inspiring, supportive letter from Long -- who was freed from prison in August after being wrongfully incarcerated for 44 years, and battled for his freedom for decades.
"Dear Archie, my name is Ronny Long and I am writing from North Carolina where I served over 44 years for a crime I did not commit," Long wrote in the letter, which Williams read aloud. "Your voice and your story has touched and inspired so many people, especially me. I never gave up fighting and just last month I was finally released from prison. But my fight for justice isn't over, there are many others like us."
Reading several other letters from men and women inspired by Williams after having gone to prison, or had their loved ones sentenced to prison, brought Williams to tears.
"Knowing that I gave people hope, that is the most amazing thing in my life," Williams explained. "This journey has been the best thing that ever happened to me. I could never have imagined making it this far, I really feel like I'm living my dream. Being here in this moment, it actually means everything to me. Everything that I have gone through, I really feel that it was fate that led me this way."
When it came time to perform, Williams delivered in a big way that hit everyone right in the feelings.
The soulful singer hit the stage wearing a chic maroon suit and he belted out a powerful rendition of the Beatles' "Blackbird" that brought a whole new meaning to some of the beloved tune's already potent lyrics.
Williams' imbued the lines "All your life, you were only waiting for the moment to be free," with the weight of his own painful experiences, and then made a subtle but important change to the last chorus, switching to a first-person voice -- essentially changing "You" to "I."
"All my life, I was only waiting for this moment to be free," Williams sang, fighting back tears as he closed out the song with stoic grace.
"The songs you pick are all songs I know but when I hear you sing them, the meaning is so much clearer and so much more pointed to you," judge Howie Mandel marveled after the performance. "I love what you do I love that the world got a chance to meet you."
Sofia Vergara shared similar praise, telling Williams, "It was moving, it was beautiful. You made this song your song. I definitely think this was your best performance."
"When I hear you sing this too, I hear it differently than I've heard it before," Heidi Klum said. "It seems like the Beatles wrote it for you, Archie."