Born in Glasgow, where she studied at the School of Drama, she would go on to train for the stage at the Central School of Speech and Drama in London. Known for her beauty, Ure began performing on the London stage and quickly developed a reputation for her abilities as a dramatic actress.

While starring in John Osborne's play, Look Back in Anger, she began a relationship with the married Osborne and after he obtained a divorce they married in 1957. Mary Ure went to New York City in 1958 to star in the Broadway production of Look Back in Anger and earned a Tony Award nomination for "Best Dramatic Actress." The highly successful play would be translated to film in which Ms. Ure reprised her role alongside Richard Burton. In the meantime, her marriage to John Osborne was already in difficulty and in 1959 she began an affair with actor Robert Shaw whom she would eventually marry.

In 1960, she appeared in the film Sons and Lovers for which she was nominated for both the Golden Globe Award and the Academy Award for Best Supporting Actress. In 1961 she took time off to begin a family and only returned to motion pictures two years later. In 1967, she appeared in a film with her husband Robert Shaw then the following year teamed up again with Richard Burton and up-and-coming actor Clint Eastwood in the box office success, Where Eagles Dare.

Mary Ure did not return to film for another five years but did perform on stage. However, her personal life was in turmoil and her growing alcoholism affected her career to the point where she was fired from the 1974 pre-Broadway production of Love for Love and replaced by her understudy, Glenn Close.

In April of 1975, she appeared on the London stage with Honor Blackman and Brian Blessed in the Don Taylor play, The Exorcism. After the opening night, Mary Ure died from what was said to be an accidental overdose from a combination of alcohol and barbiturates. However, because of her personal problems, there has always been considerable speculation that the 42-year-old actress committed suicide. The circumstances of her death led the press to talk of a "curse" on the production in which she was appearing.