Born on March 9, 1953 in Boston, Massachusetts, Koslow's mother was a docent, and was raised with a strong love for colonial life along with her sister, Linda and her brother, Donald. Koslow was educated at the University of Massachusetts Amherst and Virginia Polytechnic Institute & State University, graduating with a degree in theatre and costume design. Koslow signed on with a summer stock theater group in Virginia as a costume designer. She was also asked to audition for the role of Vera in the play "Ten Little Indians." Koslow soon put her costume designing talent aside to become a full-time actress, appearing in such regional productions as "Cat on a Hot Tin Roof" and "Dial M for Murder". She then moved to Los Angeles to pursue a television career and landed various guest roles before scoring the role of the scheming Lindsay Wells on the hit CBS soap opera The Young and the Restless (1973) which she played from 1984-1986. She was then asked by the serial's creators William J. Bell and wife Lee Phillip Bell to become an original cast member on the duo's new sister soap The Bold and the Beautiful (1987) which debuted in the spring of 1987. She portrayed Eric Forrester's (played by John McCook) design assistant Margo Lynley from the serial's inception until 1992 when she left to begin a family. Through the early 1990s Koslow busied herself with guest starring roles in several prime time television series including Silk Stalkings (1991) and The Nanny (1993). However, she was lured back to daytime television in 1996 in order to replace actress Deborah Adair who left the NBC soap Days of Our Lives (1965) to, ironically, spend more time with her family. In the role of vindictive call girl turned corporate executive Kate Roberts, Koslow flourished on Days of Our Lives quickly becoming a woman fans 'love to hate'. The character is known for her wickedness and deception, specifically her ongoing war with fellow Salem resident Sami Brady (Alison Sweeney) and her rocky marriage with mogul Victor Kiriakis (John Aniston). In contrast to her reel life, in real life Koslow has been married to make-up artist Nicky Schillace since 1987. The couple resides on a ranch in Northridge, California in the San Fernando Valley with their 2 children and various animals.