Hines was one of four children born in Dedham in Norfolk County, Massachusetts, to an actress mother and a Boston-based teacher/acting coach father.

Hines made a guest appearance on the CBS western series Johnny Ringo as Lily in the episode "The Assassins."

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 for and won the role of Wilbur Post's wife Carol on Mister Ed, which was her best-known character.

She continued on Mister Ed until the series ended in 1966, then took guest parts on television shows such as Love, American Style; Bonanza; and The Mod Squad[6] before she retired in 1971.

[citation needed] Young and Hines performed together in 1996 in Irvine, California, in the two-person play Love Letters, which deals with the correspondence of a man and woman over fifty years.