For co-founding and leading Women for Peace, a Northern Irish activist organization that was later re-named the Community for Peace People, Maguire was awarded the Nobel Peace Prize.
Before becoming an activist, she worked at the Guinness Brewery and spent her free time volunteering for a Catholic service organization called the Legion of Mary.
She joined her country's movement for peace after her niece and two nephews were killed in an automobile-pedestrian accident involving an on-the-run member of the Provisional Irish Republican Army. Tragically, the children's mother (Mairead Maguire's sister Anne) committed suicide following the event.
In the early 1980s, she and her husband Jackie Maguire (who was previously married to her deceased sister, Anne) welcomed sons named John Francis and Luke.
She and one of her fellow Women for Peace founders, Betty Williams, were co-recipients of the 1976 Nobel Peace Prize.