The Mississippi native had been battling breast cancer.
After her reign as Miss America in 1959, Mobley got her start on television shows such as Burke's Law in 1963 and Perry Mason in 1964. In 1965, she starred opposite Elvis Presley in a pair of movies, Girl Happy and Harum Scarum, and took home the Golden Globe award for New Star of the Year.
Mobley appeared in several more films, including Three on a Couch, The King's Pirate and For Singles Only, before returning to the small screen. She recurred on Fantasy Island and The Love Boat. In 1985, she replaced Dixie Carter as Maggie McKinney on the final season of Diff'rent Strokes. Mobley would later guest-star on Carter's series, Designing Women.
Mobley also made multiple appearances on The Match Game as a guest celebrity.
In her personal life, Mobley was married to the late actor and TV host Gary Collins, whom she met on the set of Three on a Couch. Collins passed away in 2012. Mobley is survived by her daughters, Mary Clancy Collins and Melissa Collins, her son Guy William Collins, her sister Sandra Young and two grandsons.