On September 28, 2004 (her birthday), she released her second album, the self-titled Hilary Duff. She says that it has an edgier, rock feel into it. The album was supposed to be called The Girl Can Rock. Its first single is Fly, and it also includes Haters, which is rumored to be about Lindsay Lohan, who is sometimes considered to be Duff's enemy.

She started her acting career early in the 1990s with movies like Mi Familia, Money Train, and U-Turn, but her breakthrough was the part of Selena Quintanilla in the movie Selena. She followed this with a well-received performance in Out Of Sight with George Clooney. She has also appeared in Anaconda, The Cell, Angel Eyes, The Wedding Planner, Enough, Maid in Manhattan, Gigli, Jersey Girl, and Shall We Dance, Monster-In-Law