Flintoff beat Australian Football League player Barry Hall and TV personality Chrissie Swan to the title in the South African jungle.
After winning, Freddie said: "As an Englishman winning something in Australia, it's unheard of."
On the show he ate a rat's tail and was covered in elephant manure.
He also drank fermented milk laced with cockroaches and flies and fell out of a helicopter.
Speaking about his month in the jungle, he said: "I'm shocked. I'm stuck for words a little bit. I never expected to get this far. It's a lot to take in really. I am shocked, surprised, pleased.
"I've got a lot of emotions going round at the minute. I'm humbled."
His win will see 100,000 Australian dollars (Â£50,635) donated to his chosen charity, the McGrath Foundation.
While on the show the 37-year-old talked about how giving up alcohol had changed his life.
He said: "One, I genuinely thought I'd had enough of it. It catches up with me in the morning.
"And two, I suffer with depression and it doesn't help at all. I just hit rock bottom afterwards. So you're far better without it."
Flintoff retired from professional cricket in September 2010 but came out of retirement last year to play for Lancashire in the T20 Blast.
Before his time in the South African jungle, he'd been in Australia playing for Brisbane Heat in the Twenty20 Big Bash.
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Andrew Flintoff has been crowned Australia's king of the jungle after winning their version of I'm A Celebrity... Get Me Out Of Here!