Peters was born in Halewood, Lancashire, but moved to Ballymena at age eleven when her father's job was relocated to Northern Ireland. She now lives in Lisburn just outside Belfast. As a teenager, her father encouraged her athletic career by building her home practice facilities as birthday gifts. She qualified as a teacher and worked while training.
Athletics career
After Ballymena, the family moved to Portadown where she attended Portadown College. The headmaster Donald Woodman and PE teacher Kenneth McClelland introduced her to athletics with Mr McClelland her first coach. She was head girl of the school in 1956. In the 1972 Summer Olympics in Munich, Peters competing for Great Britain and Northern Ireland won the gold medal in the women's pentathlon. She had finished 4th in 1964 and 9th in 1968. To win the gold medal, she narrowly beat the local favourite, West Germany's Heide Rosendahl, by 10 points, setting a world record score. After her victory, death threats were phoned into the BBC: "Mary Peters is a Protestant and has won a medal for Britain. An attempt will be made on her life and it will be blamed on the IRA... Her home will be going up in the near future." But Peters insisted she would return home to Belfast. She was greeted by fans and a band at the airport and paraded through the city streets, but was not allowed back in her flat for three months. Turning down jobs in the US and Australia, where her father lived, she insisted on remaining in Northern Ireland. In 1972, Peters won the BBC Sports Personality of the Year award. "Peters, a 33-year-old secretary from Belfast, won Britain's only athletics gold at the Munich Olympics. The pentathlon competition was decided on the final event, the 200m, and Peters claimed the title by one-tenth of a second." She represented Northern Ireland at every Commonwealth Games between 1958 and 1974. In these games she won 2 gold medals for the pentathlon, plus a gold and silver medal for the shot put.
Peters established a charitable Sports Trust in 1975 to support talented young sportsmen and women, both able-bodied and disabled, from across Northern Ireland. The Trust now known as the Mary Peters Trust, helps aspiring young athletes realise their maximum potential by assisting them in both a financial and advisory capacity. Since its inception more than 40 years ago, the Mary Peters Trust has made a staggering number of Awards making a difference to the lives of thousands of young athletes from across Northern Ireland. The Trust has a very impressive list of alumni including Graeme McDowell, Rory McIlroy, Jonathan Rea, Darren Clarke, David Humphreys, Bethany Firth, Ryan Burnett, Carl Frampton, Paddy Barnes, Michael Conlan, Kelly Gallagher, Michael McKillop, Dr Janet Gray, and many more.