The news follows the announcement on Thursday of boss Karl Robinson signing a new three-year deal.
Former Swindon, Wycombe and Northampton manager Gorman told Dons` official website: "I am really pleased. When I joined Karl last year I did not know too much about the club or the players, but I have really enjoyed my 12 months here and it has been a pleasure working with the lads every day.
"My appetite for football remains as strong as ever. Karl, the staff and I have a shared ambition to move this club forward and I believe we are heading in the right direction."
Robinson added: "John has been fantastic for me. I can only speak highly of him because he is an absolute gentleman with an unbelievable wealth of football knowledge.
"Without him we wouldn`t be where we are today and my thanks go to him."
Source: PA
Source: PA