In 1974, she was cast by Sid and Marty Kroft to play Holly Marshall, the younger of two siblings trapped with their father in a strange land in Land of the Lost. It was her only major television role, which continued for three seasons. She contributed interviews and commentary tracks for the Land of the Lost DVDs produced by Rhino in 2004. She and fellow Land of the Lost cast member Wesley Eure filmed cameos for the 2009 film parodying the series, but those scenes were not included in the theatrical release.

She appeared in an episode of the police drama Adam-12 in 1975.

In 2015, Coleman published Lost Girl: The Truth and Nothing But the Truth, So Help Me Kathleen, which describes two abusive marriages as well as her experiences in music, TV, and on the autograph circuit.  In 2017, she published a second memoir, entitled Run Holly Run, which highlighted her time working on Land of the Lost.

Kathy appears courtesy of Celebworx.