She made her big screen debut in the 1965 Western film Shenandoah, for which she received Golden Globe Award nomination for New Star of the Year – Actress.

[3] Her father, David Forsyth,[4] was Scots-Canadian; her mother was an Irish American[5] who worked as a model in New York using her maiden name, Rosemary Collins.

[3] Educated in Stockbridge, Massachusetts,[6] she added to her acting studies by attending the Wynn Handman Drama School in New York.

"[7] Forsyth made her big screen debut in 1965 in the Western film Shenandoah from Universal Pictures as James Stewart's daughter.

[9] Later that year, Forsyth starred in the epic historical film The War Lord with Charlton Heston, playing the female lead.

[10] In 1966, Forsyth played the female lead in the western comedy film Texas Across the River with Dean Martin and Alain Delon.

[12] She returned to cinema in 1969, starring alongside David Janssen in the drama Where It's At for United Artists,[13] neo-noir thriller What Ever Happened to Aunt Alice?

She made appearances on Night Gallery, Kung Fu, Mannix, Barnaby Jones, Petrocelli, Charlie's Angels and CHiPs.

Since then, Forsyth appeared in made-for-television movies and series, notable having guest shots on Murder, She Wrote, JAG, Star Trek: Voyager, Chicago Hope, Dharma & Greg, ER and Ally McBeal.

[25] She has since appearanced on Boston Public, Monk, NYPD Blue and Without a Trace, as well made-for-television films A Time to Remember (2003) and Sweet Nothing in My Ear (2008).