كتب : وكالات
The 35-year-old ended a second spell with Arsenal, whom he joined last January, to move to Newcastle.
"At this stage I couldn’t have wished for a better move," Campbell told Newcastle's official website.
"I'd like to thank (manager) 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.
"I just want to play and can't wait to get started."
Campbell began his career at Tottenham Hotspur before joining Arsenal and then Portsmouth.
He won with the Gunners two Premier League titles, four FA Cups and one League Cup.