Mary Coughlan was born in Galway City, Ireland. She was the eldest of five and endured a very erratic youth. As a teenager, she began drinking and taking drugs leading to a spell in hospital. After her leaving cert, she moved to London where she had a brief career as a street sweeper and she lived in a squat. A couple of years later, she returned to Ireland, married and had three children in quick succession by the age of twenty-four.

In 1985, Mary released her first album Tired and Emotional. Around this time, her marriage broke down and Mary took custody of her children. Her first album was a huge overnight success and she went from obscurity to being a household name in weeks, partly due to a memorable appearance on The Late Late Show, the first of many. She acted in Neil Jordan's High Spirits in 1988.