Ashley Michelle Tisdale was born in West Deal, New Jersey, to Lisa Morris and Mike Tisdale, and has an older sister, Jennifer, who is also an actress. She is of Jewish ancestry, and her maternal grandfather is Arnold Morris, the developer of Ginsu Knives. Tisdale was discovered by her current manager, Bill Perlman, at her hometown mall in Monmouth County when she was three. She sang at the White House when she was twelve years old.

Tisdale began acting in the late 1990s, appearing in episodes of several television series, including Smart Guy, 7th Heaven, Grounded for Life, Boston Public, Strong Medicine, Charmed and Beverly Hills, 90210. She had a minor role in the 2001 film Donnie Darko and recurring roles on the sitcoms The Hughleys and Still Standing. Tisdale auditioned for the roles of Maddie Fitzpatrick and London Tipton on The Suite Life of Zack and Cody and was cast as Maddie. She was ultimately happy to receive the role because she wanted to portray a character that she felt was more like herself.[7]

As The Suite Life gained in popularity, she became a featured performer on the Disney Channel, appearing in several promotions, specials, and ads for the network. She was also cast in Disney's television film High School Musical, which became a major success for the channel. The role required Tisdale to perform several songs including, "What I've Been Looking For," "Bop to the Top," and "We're All in this Together". All three managed to chart on the Billboard Hot 100. She has also recorded versions of the songs "Someday My Prince Will Come" (from DisneyMania 4 CD) and "Kiss the Girl" (for the DVD special edition release of The Little Mermaid) for Disney, which debuted at number 16 on Radio Disney.[citation needed] In addition, she is part of the current Disney Channel Circle of Stars, and has sung a version of "A Dream is a Wish Your Heart Makes".

Tisdale appeared in the Disney Channel Games, which began airing in June of 2006; she is a member and captain of the Green Team, alongside with Lucas Grabeel, Miley Cyrus, Emily Osment, Mitchel Musso, and Kyle Massey. In July of 2006, Tisdale signed a deal with Staples, Inc.; she will appear in the promotional campaign for the company's "Geared 4 School" sweepstakes during the fall of 2006.