Scarlet Ingrid Johansson was born in Manhattan, New York City, on November 22, 1984. She attended Public School 41, an elementary school in Greenwich Village. She was interested in performing from an early age, putting in song-and-dance routines for her family. Johansson grew up loving musical theatre and jazz, and her parents supported her, enrolling her in dance classes and acting lessons. Her parents enrolled her at the Lee Strasberg Theatre Institute in New York City and allowed her to begin auditioning for commercials.
Johansson made her professional stage debut in the off-Broadway play Sophistry, in which she had two lines. As her professional engagements increased, her parents enrolled her at New York City’s Professional Children’s School. Johansson made her film debut in the fantasy comedy North when she was only nine years old. Her first leading role was in 1996’s Manny & Lo as Amanda, the younger sister of a pregnant teenager who runs away from her foster home.
In 1998, she portrayed an injured teenager who works with a talented horse trainer to nurse her horse back to health, as well. Her breakthrough came in 2001 in the black comedy Ghost World. She graduated from the Professional Children’s School in 2002 and applied to New York University’s Tisch School of the Arts, but she was rejected and decided to throw herself into her work.