When she auditioned for the role at the age of 5, Mackenzie impressed producer Aaron Spelling and others by walking up to each individual in the room, shaking hands and introducing herself. In addition to her role on the drama series, Mackenzie appeared in the independent film Gideon's Web, starring Christopher Lambert, Charlton Heston and Shelly Winters. She also played the controversial role of JonBenet Ramsey in the telepic Getting Away With Murder: The JonBenet Ramsey Mystery and has appeared in numerous national commercials.

She currently resides in Los Angeles, Calif. with her family and a house full of animals.