Melissa Sue Anderson Plays Mary Ingalls Melissa Sue Anderson was the perfect actress for the Mary Ingalls part in Little House on The Prairie.  Melissa won the Park of Mary Ingalls up against scores of aspiring actresses trying out for the part.  She was born on the 26th of September 1962, and was Millicent on the Brady Bunch and went on to play in a few more TV series one being Murder, She Wrote.  She's married and two kids, she was also accepted into the Western Performers Hall of Fame..  Melissa Sue Anderson played in may other TV Series, and films, but is best known for her roll as Mary Ingalls