Mack also starred in Showtime's critically acclaimed feature My Horrible Year! This story follows the intricate and turbulent life of a teenage girl as she turns sixteen. Mack, who brought years of training and experience to the project, proved to be the perfect fit for Eric Stoltz's directorial debut. The story was written and directed by Eric Stoltz and also starred Karen Allen and Mimi Rogers.

Since beginning her career at age 4 in her first commercial for "German Chocolate," Mack has continued to be a busy working actress with an impressive roster of television roles. She garnered much attention for her portrayal of a teenager who abuses and inflicts wounds to her wrist on The WB's Seventh Heaven. In the fall of 2000, Allison starred in The WB's The Nightmare Room, and The Opposite Sex, as well as a recurring role in Evening Shade. Allison also starred in Disney's feature Honey, We Shrunk Ourselves and Camp Nowhere.

An avid fan of musical theatre, Allison's talents extend beyond film and television. She received rave reviews for pulling double duty, both as a choreographer and performer in Rent and Chicago. As a result of those performances, Allison was offered the chance to make her directorial debut with Jer Bear Productions' staging of Hair. Rave reviews from LA Weekly, Backstage West, The Tolucan Times and The Burbank Times all attest to Allison's diversity in the entertainment field. Music and dance, as much as acting, remain a passion for Allison.