Hines was one of four children born in Dedham in Norfolk County in eastern Massachusetts to an actress mother and a Boston-based teacher/acting coach father. As a child, she appeared in many of her father’s stock-company plays. A member of the class of 1948 at Dedham High School, she was voted the most popular girl in her class. She dated the captain of the football team and was class secretary. She tried out unsuccessfully for a part in the senior class play. After her father’s death, she went on to marry an insurance agent and moved to Jacksonville, Florida. She worked as a model there and as a radio and stage actress and joined a stock company in Miami. By the time she was divorced, Hines traveled to New York City to study with the Helen Hayes Equity Group. When she came to Hollywood, she lived in an apartment, rented a car and began acting with a role on an episode of the syndicated television series, Whirlybirds. Hines’s first film role was in 1960’s Thunder in Carolina. She also appeared in an episode of Sea Hunt in 1960 S3E33. She made guest appearances on two CBS series, the western, Johnny Ringo as Lily in the episode “The Assassins.” She also made a guest appearance on an episode of Bachelor Father starring John Forsythe and two guest appearances on Perry Mason. In 1960 she played defendant Lucy Stevens in “The Case of the Singular Double” then later played Sandra Dalgran, the wife of a murder victim, in the 1962 episode, “The Case of the Counterfeit Crank.”

Hines was cast as Lucy Bridges in the 1960 episode, “Chicota Landing” of the Darren McGavin NBC western series, Riverboat, along with Richard Chamberlain as a United States Army lieutenant. Hines auditioned and won the role of wife, Carol Post, on Mister Ed, which was, arguably, her best-known character. Hines considered her role to be just getting a steady paycheck as the storylines focused more on the relationship of Wilbur and Mister Ed (the talking horse) than her. She also said that playing the same role wasn’t the greatest part in the world. Around the same time, she took some acting, dancing and music classes. She continued playing that role until 1966. After the series ended she took guest parts on such television shows as Bonanza and The Mod Squad before she retired in 1971. Young and Hines performed together in 1996 in Irvine in the two-person play Love Letters, which deals with the correspondence of a man and woman over fifty years. Hines died from heart problems on December 18, 2009 at her home in Beverly Hills, California.