It is not known where she was born but she spent many years in New York City with her husband and daughter. Shortly before the events of Kristy's Great Idea, Edward was transfered to a Stamford branch of his law office and the family moved to 612 Fawcett Ave., Stoneybrook. Maureen, Stacey, and Edward moved back to New York City when Edward was re-transferred back to the New York office (Good-bye Stacey, Good-bye). During their second period in New York, Maureen and Ed's relationship became rocky, with many fights about money, work, and respect; Ed called Maureen a spendthrift and accused her of wasting his money, and Maureen called Ed a workaholic. Later, Maureen also suggested that she lost respect for Ed because of his choice to leave public defense for corporate law (Stacey McGill... Matchmaker?) Maureen and Ed decided to divorce, and Maureen moved with Stacey back to Stoneybrook (Welcome Back, Stacey!).
Maureen can sometimes be a bit overprotective of Stacey because of Stacey's diabetes. Whenever she has to say good-bye to Stacey in New York City (even if Stacey is just going downstairs or down the street), Maureen always tells Stacey to "have fun and be careful."
Maureen can be a bit of a shop-a-holic like Stacey. When Stacey goes off to Camp Mohawk, everyone jokes that she will make Bloomingdale's department store go broke.
Maureen did not work while she was married, but after the divorce, she got a job as a buyer for Bellair's Department Store (Stacey's Choice). Maureen has a brother named Eric Spencer who is married to Carla Brown and they have a daughter named Cheryl (as revealed in The Truth About Stacey) whom Stacey does not like very much.
In Friends Forever #10 Stacey's Problem, she changes her name back from Maureen McGill to Maureen Spencer, in part because Stacey's dad is getting remarried.