The 18-year-old, from South Shields, beat Olly Murs in the public vote in the final of the show.
McElderry beat 200,000 applicants to The X Factor and more than 10 million public votes were cast.
He hugged his mentor, fellow Geordie Cheryl Cole, and said: "I can't even speak, thank you so much everyone."
He added: "I can't actually speak and I just want to say thank you to Cheryl, she's been an amazing mentor."
He also thanked the other judges and everyone who voted for him.
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