The 35-year-old has signed a one-year contract with the Magpies.
Campbell will join Newcastle on a free transfer as his contract at Arsenal expired at the end of last season.
Sunderland and Celtic were also reportedly interested in signing the defender.
“At this stage of my career I couldn’t have wished for a better move,” Campbell told the club’s official website.
“To join a club such as Newcastle United, with its proud tradition, heritage and magnificent support, is absolutely tremendous for me.
“I’d like to thank Chris Hughton for putting his faith in me and aim to repay him and the supporters by giving everything I possibly can to help re-establish this great club in the top tier of English football.
“There’s a real buzz about the place and that’s great. I’ve played at St James’ Park numerous times and always found it a fantastic place to play, there’s always a tremendous atmosphere.”
Magpies boss Hughton added: “I have known Sol since he was a lad at Tottenham and am fully aware of what he has to offer. That is experience, quality, calm assurance and leadership.
“He’s a dedicated professional, a terrific addition to the squad, and I look forward to working with him again.”
