Hayden Panettiere began her career at the age of only 11 months, appearing in advertisements for a toy train of Playskool. At age of four, she stars as Sarah Roberts on the ABC soap opera One Life to Live, where she will remain in the cast from 1994 to 1997. From 1997 to 2001 plays Lizzie Spaulding in The Guiding Light, a character has to face a battle against leukemia. The soap opera has received, for having attracted the attention of the viewers of this disease, a special award from the foundation Leukemia & Lymphoma Society. In 1998, she left the world of soap operas and made her debut in the film, playing a role to appearance in the film The Object of My Affection. Later appears in other films, such as Remember the Titans, Message in a Bottle, Raising Helen, and in the television series Ally McBeal (where she played the daughter of the protagonist), Malcolm and Law & Order. In 2004 she starred in the television movie Tiger Cruise, while in 2005 she played the role of Jennifer Harvood in the film Ice Princess, directed by Tim Fywell, and a year later the heroine in Bring It On: All or Nothing.
Since 2006 she plays the role of Claire Bennet, a cheerleader with the power of cell regeneration, in the NBC series Heroes. This role has given her reputation worldwide thanks to the regular participation in conferences on science fiction drama held around the world as well as in various editions of the Comic-Con. Later she appeared in the drama Fireflies in the Garden, in the role of the character of Jane Lawrence young.
From June 2007 she is represented by the agency William Morris, whereas previously had a contract with the United Talent Agency. Forbes estimated that Hayden earned about $ 2 million in 2007..
In September 2008, she appeared in a satirical video entitled Hayden Panettiere PSA: Your Vote, Your Choice. Subsequently, in October, she appeared in a similar video entitled Vote for McCain: it’s just like George Bush, except older and with a worse temper.
In 2009, Hayden Panettiere starred in the comedy I Love You, Beth Cooper; while in 2011 accepts the role of the protagonist in the controversial TV movie Amanda Knox, she replaced Anne Hathaway in Hoodwinked Too! Hood vs. Evil and was co-starring in the movie Scream 4 playing the role of Kirby Reed. Since 2012 she acted in the television series Nashville.
Hayden has lent her voice to the female protagonist of the Kingdom Hearts series, Kairi, in the versions of the game dubbed in English. In 2015, Hayden has lent her face and physique to one of the protagonists of the game Until Dawn.