Apollo secretly had an affair between the events of Rocky III and Rocky IV with Adonis Creed's unnamed biological mother, Ms. Johnson. Unfortunately, Apollo died in the ring against Ivan Drago, and Donnie's mother died while he was still very young. The last time Rocky and Mary Anne would speak would be at Apollo's funeral. Devastated by the loss of her husband, Mary Anne remained angry for a long time, hurting herself and pushing family away.
Thirteen years after Apollo's tragic death, Mary Anne by this time had uncovered Adonis' existence. She decided to pay Donnie a visit in the Los Angeles youth facility where he was living. She adopted Donnie and raised him as her own son at the Creed estate. He would fully accept her as his second mother.
In 2015, Donnie made his decision to pursue boxing full time and move to Philadelphia, wanting to tell Mary Anne in person. As he rather sadly expected, Mary Anne refused to give her blessing and told him to not bother calling home. He would leave at least one message after settling in, adding that he missed her, but it is not shown if she ever returned it.
Mary Anne would keep up with the news, and after Donnie added the Creed name to his own to fight 'Pretty' Ricky Conlan, she sent a gift to Team Creed's dressing room in Liverpool along with an encouraging note: American flag shorts like Apollo and Rocky wore, with 'CREED' on the front band and 'JOHNSON' on the back band. She watched the fight on television and was proud of him for becoming the first person to knock Conlan down.