Louis Knight, a Lower Merion High School graduate, wrote "Change" in honor of his friend, Russell Peck, who died by suicide in 2018.
"He became a part of the family instantly. He was always so supportive of my music," said Knight about his friend on Sunday night.
Knight said he and his brother bonded with Russell over soccer, and news of his death rattled his family's world.
"We knew he was going through a hard time, we didn't know the extent of that suffering," Knight said. "All I can hope for this song is maybe it can speak to someone suffering and maybe save a life."
The judges were wowed by Knight's song choice.
"I think he might be the biggest star we have on American Idol," said Luke Bryan.
"I wouldn't go so far to say you're the biggest star we've seen in these three seasons, got to keep you humble, got to keep you wanting it, but I really appreciated your original song. I appreciate the sentiment of it," said Katy Perry.
"You're on to something big," said Lionel Richie.
And with that -- the judges sent Knight to Hollywood.
The 19-year-old singer-songwriter auditioned for the judges in Washington D.C.
"This is the American Dream," Knight told Action News on Monday morning. "We moved here because we needed money and my dad needed a new job. It's been a dream come true."
A 2018 graduate of Lower Merion, his parents graciously gave him a year to pursue his music.
"Kind of like an open-ended gap year," he said.
Knight's family moved to Narberth from England eight years ago, leaving behind friends and extended family.
"Moving away from all of that was a bit difficult and then starting right in middle school, well, that's a tough time for anyone," he said.
That's when he says music found him.
"I got my first piano for Christmas and then I wrote my first song," he said. "I was a freshman at Lower Merion."
That singer-songwriter thing? Seems he was born with it.
"Since I was a baby, I was humming the whole time," he laughs. "And then my dad was in a band."
Knight said he is now a full-fledged Philly guy.
"I love Philly. This is our home."
By day, he's in the studio working on his new album. By night, he delivers pies for Narberth Pizza.