The Disney film, which co-starred Julie Andrews, was a commercial success and Hathaway was widely praised for her performance.
The 28-year-old continued with the family-friendly films for the next three years, reprising the role of Mia in the Princess Diaries sequel in 2004, as well as Ella Enchanted.
Like Andrews however, she began to branch out into more dramatic roles, pointedly moving away from the children-friendly films, with a performance as a spoiled socialite in Havoc.
She gained attention from a more adult audience thanks to a supporting role in Brokeback Mountain, the critcally successful film starring Heath Ledger and Jake Gylenhaal about the complex romantic relationship between two cowboys.
She followed this up with the starring role in The Devil Wears Prada, playing the assistant to Meryl Streep's Miranda Priestly, widely believed to be inspired by Anna Wintour, the editor of Vogue. The film went on to gross more than $300 million.
As she gradually became one of the more recognisable faces in Hollywood, Hathaway has appeared in a wide ranging mix of films, both comedy and drama, ranging from Get Smart, the spy comedy caper, to Becoming Jane, where she played the author Jane Austen.
She has won the most praise however for her film Rachel Getting Married, where she was nominated for an Academy Award for Best Actress. Hathaway's character Kym is released from rehab for a few days so she can go home and attend the wedding of her sister Rachel. Hathaway won rave reviews for her portrayal of Kym, and she picked up a number of awards, but ultimately lost out to Kate Winslet for the Oscar.
Last year she played the White Queen in Tim Burton's 3D epic Alice in Wonderland, while at the other end ofthe spectrum she starred alongside her Brokeback Mountain co-star Gyllenhaal in the comedy-drama Love and Other Drugs.
Hathaway has also had a colourful personal life. Two-and-a-half years ago, she went through a very public break-up with Italian businessman Raffaello Follieri. He is serving a four-and-a-half year sentence for cheating investors out of millions of dollars, after falsely claiming he had Vatican connections that helped him buy church property at a discount.
Admitting that she is a "very trusting" person, she freely admits that it was a "bad relationship".
She is now in a relationship with Adam Shulman, the actor and filmmaker.