Mary Anderson was the daughter of Bob and Phyllis Anderson. In 1974 when Mary's mother Phyllis tried to murder Julie Olson Banning Anderson, Mary was hit by mistake, but lived. In 1977 Mary had a brief affair with her mother's husband Neil Curtis. Later that year Mary began seeing Chris Kositchek. When Chris quit Anderson to form his own company Mary supported him, but they both returned to Anderson when Bob personally asked them back. Later that year after Linda and Stephanie Woodruff began dirty dealings in the company Mary confronted her father about Linda and Neil, and Bob quickly investigated the alleged affair and took away Linda's power at the company. Chris asked Mary to marry him, but when she turned him down they broke up. Later when Chris moved in with Amanda Howard Peters, Mary re-thought her actions and decided to fight for Chris. One day while arguing with Chris she was accidentally hit by his car when he attempted to drive off.

By the end of 1979 Mary became involved with Alex Marshall, and in March of 1980 she and Alex married. At their wedding Mary's father Bob Anderson suffered a heart attack and died. Later that year Mary learned that Alex had only married her because he was helping two different men to take over Anderson Manufacturing, and she divorced him and kicked him out of the business. She also learned David Banning was in on the takeover and told him to leave town as well. In 1981 Mary was jealous of Marie and Alex's relationship, and she set out to sabotage it. In 1982 Mary was murdered by the Salem Strangler, and she left Anderson to Melissa and Phyllis Anderson.