The 28-year-old former Port Vale and Hereford man left Mansfield on Friday by mutual consent after seven appearances.
And the Minstermen moved quickly to snap up the defender on a two-and-a-half year deal.
Boss Nigel Worthington told the club's official website: "The Chairman and myself have worked hard over the last month or so to try and bring John into the football club.
"He's an experienced player at League 2 level, has played a wealth of games and has captained Port Vale during their promotion season."
McCombe added: "I'm really excited. Obviously I'm glad to get it all done after working hard on it for the past week or so."
- Sports & Recreation
- Port Vale