Born and raised in the San Fernando Valley of Los Angeles, Mckenzie was the third child of makeup artist Micheal Westmore and wife Miriam. Her first feature film appearance came at the age of 3 when she played Robert DeNiro's (as Jake LaMotta) daughter in the Oscar-winning Raging Bull. She also has made appearances in the film Star Trek 9: Insurrection, television shows Star Trek: Voyager, Weird Science, Star Trek: The Next Generation Days of Our Lives. McKenzie also filmed a guest appearance on the hit comedy Friends.
Mckenzie has extensive theater training that includes the Lee Strasberg Theatre Institute and the Uta Hagen Master She is a trained opera singer and has appeared on stage in "Dido & Aneas," "The Sound of Music" and "The Little Shop of Horrors."
In the role of Sheridan Crane, McKenzie is the stunning and compassionate daughter of Passions patriarch Alistair Crane, who can't stand to see his daughter happy, having attempting to kill Sheridan on several occasions. McKenzie's portrayal of Sheridan earned her a 2001 Soap Opera Digest Award for Outstanding Heroine.
While on the set of Passions, McKenzie met the man who became the love of her life, her husband Keith Volpone of Seven and the Sun, and were married in May of 2002.