Plus, the 15-year-old fan favorite shared how Blake Shelton reacted to getting beat by Team Gwen!
ET's Cassie DiLaura spoke with the 15-year-old performer from Shoreham, New York, on Wednesday after his big win, where he admitted he was "still in shock."
"I'm just so grateful and so blessed, because there's been so many incredibly talented singers this season," he raved. "I think my win was due to Gwen's coaching. She's phenomenal."
Carter became the youngest-ever male winner of The Voice on Tuesday night, after wowing the coaches all season with his powerful vocals and mature stage presence. And he said his time on the show was a literal dream come true.
"It means everything and more," he said. "I'm a huge fan of the show, I've been watching the show forever. I was just thinking back to literally a year ago, I was watching Gwen Stefani on TV and I was joking about it with my family, like, 'Imagine that I get on the show and get to work with her and sing a duet with her,' and literally, my dreams came true."
Carter and Gwen took the stage together on Tuesday's live finale, performing her holiday hit, "You Make It Feel Like Christmas," but the pair's biggest moment came when host Carson Daly announced him as the season 19 winner -- and the first-ever champion from Team Gwen!
"We both did not believe what was happening. We're both still trying to process it," Carter recalled with a laugh. "We've built a very close bond. She's so down to earth and so genuine… She definitely wanted the best for me, she's worked so hard to get to this point. She just really believes in me, which means the world."
"He was honestly, super happy for me and Gwen. He said, 'If I were to lose to anyone, I'm glad it's you and Gwen. You could tell he was truly happy for us."
Gwen certainly has plenty of advice to hand down to her young champion. The No Doubt frontwoman was just a teenager herself when her own musical career began, and Carter said his coach has told him "this is the perfect time for me to start writing songs, and I completely agree."
"I want to keep expanding on my music career," he added. "I plan on writing a lot of songs and getting in the studio and recording them, and once COVID is over I want to perform in front of live audiences again. I really miss the adrenaline you get from live performance."
Earlier this season, Carter told reporters that, style-wise, he hoped to emulate male singer-songwriters who have seen success on the pop charts in recent years, naming Lewis Capaldi, Harry Styles, Ed Sheeran and Shawn Mendes as some of the artists he admires.
During Monday's live finale, the young performer sang an original single, "Up From Here," which was co-written by pop hitmaker Justin Tranter. Carter said that the new track definitely "sounds like a song I want to record."
"That was really an inspirational moment for me and I want to create more songs that sound like that and release an album that would hopefully go worldwide one day. That would be my dream," he shared.
As for what he plans to do with the rest of his Voice winnings? "I haven't thought much about it yet," Carter admitted. "I want to spend it wisely, for sure, and I want to use it for good."
The Voice will return for season 20 in 2021 on NBC. See more of Carter's impressive season in the video below.