He also added that he's grateful for his time at Breakfast and will miss his co-stars, Clarkson, Stewart and McLean dearly.
"They're wonderful people, and we're friends, and that matters when you're starting work at four am, and doing three hours, live, each morning in their company. I'll miss them, but I'll be back on Breakfast at regular intervals."
He also confirmed the career change on Twitter today, saying he was "kinda busting to work in the field again".
His new role as chief correspondent would see him working on specials and documentaries, he said.
"Campbell will tell stories across TVNZ's news and current affairs shows, on television and digital. He will also host a number of specials," TVNZ said.
TVNZ's head of news and current affairs Paul Yurisich shared a tribute to John who he called the "absolute best" at "telling people's stories".
"He's been a crucial part of the Breakfast team, but we're very excited to have him out and about around Aotearoa getting into the big issues and providing even more depth to our daily coverage," Yurisich said.
1. A small ☺️ announcement in the form of a thread!
After 3 years on @Breakfaston1, I'm finishing with that lovely team on Friday, to start a new role as TVNZ's Chief Correspondent.
That's really what I came to TVNZ (in 2018) to do (before Breakfast happened), it's work that...
Santamaria worked at 3 News before taking jobs overseas, most recently at Al Jazeera.
Yurisich said last month in response to speculation that Campbell would leave Breakfast: "We've started the year with the team you see - Jenny-May, John, Matty (McLean), and Indira (Stewart) and that's who's on-air at the moment."
When asked if the lineup was expected to change, Yurisich reportedly responded, "As I said, that's the team at the moment. That is the team."
Santamaria, an Auckland-born journalist, started his career as a sports reporter for Newshub before leaving New Zealand to pursue other ventures.
In the statement from TVNZ Santamaria shared the reason he decided to come back to New Zealand: "20-years is a long time to be away, but it's the challenge of Breakfast and three hours of live, on-your-feet broadcasting every morning which has brought me back."
The journalist, who spent 16 years with the Qatar-based network, also announced on air earlier this week that the news bulletin would be his last for the company.
He told viewers, "Finally this half-hour we are always taught as journalists not to make the story about ourselves but it would be remiss not to mention that today has been my last day at Al Jazeera after nearly 16 and a half years.
"It has been the most extraordinary journey, surrounded by exceptional journalists telling the stories which matter. I am so proud to have been a part of this channel and I will miss it greatly."