Answer by taking a quote from the following article:

Scarlett Ingrid Johansson was born in the Manhattan borough of New York City, New York. Her father, Karsten Olaf Johansson, is an architect originally from Copenhagen, Denmark, and her paternal grandfather, Ejner Johansson, was an art historian, screenwriter and film director, whose own father was Swedish. Johansson's mother, Melanie Sloan, a producer, comes from an Ashkenazi Jewish family of Polish and Belarusian descent. She has an older sister, Vanessa, also an actress; an older brother, Adrian; and a twin brother, Hunter.

Johansson's first leading role was as Amanda, the younger sister of a pregnant teenager who runs away from her foster home in Manny & Lo (1996) alongside Aleksa Palladino and her brother, Hunter. Her performance received positive reviews: one written for the San Francisco Chronicle noted, "[the film] grows on you, largely because of the charm of ... Scarlett Johansson," while critic Mick LaSalle, writing for the same paper, commented on her "peaceful aura", and believed, "If she can get through puberty with that aura undisturbed, she could become an important actress." Johansson earned a nomination for the Independent Spirit Award for Best Lead Female for the role. After appearing in minor roles in Fall and Home Alone 3 (both 1997), Johansson attracted wider attention for her performance in the film The Horse Whisperer (1998), directed by Robert Redford. The drama film, based on the 1995 novel of the same name by Nicholas Evans, tells the story of a talented trainer with a gift for understanding horses, who is hired to help an injured teenager played by Johansson. The actress received an "introducing" credit on this film, although it was her seventh role. On Johansson's maturity, Redford described her as "13 going on 30". Todd McCarthy of Variety commented that Johansson "convincingly conveys the awkwardness of her age and the inner pain of a carefree girl suddenly laid low by horrible happenstance". For the film, she was nominated for the Chicago Film Critics Association Award for Most Promising Actress. She believed that the film changed many things in her life, realizing that acting is the ability to manipulate one's emotions. On finding good roles as a teenager, Johansson said it was hard for her as adults wrote the scripts and they "portray kids like mall rats and not seriously ... Kids and teenagers just aren't being portrayed with any real depth". Johansson later appeared in My Brother the Pig (1999) and in the neo-noir, Coen brothers film The Man Who Wasn't There (2001). Her breakthrough came playing a cynical outcast in Terry Zwigoff's black comedy Ghost World (2001), an adaptation of Daniel Clowes' graphic novel of same name. Johansson auditioned for the film via a tape from New York, and Zwigoff believed her to be "a unique, eccentric person, and right for that part". The film premiered at the 2001 Seattle International Film Festival; it was a box office failure, but has since developed a cult status. Johansson was credited with "sensitivity and talent [that] belie her age" by an Austin Chronicle critic, and won a Toronto Film Critics Association Award for Best Supporting Actress for her performance. With David Arquette, Johansson appeared in the horror comedy Eight Legged Freaks (2002), about a collection of spiders that are exposed to toxic waste, causing them to grow to gigantic proportions and begin killing and harvesting. After graduating from PCS that year, she applied to New York University's Tisch School of the Arts; she decided to focus on her film career when she was rejected.

what was a major role for her?
Her breakthrough came playing a cynical outcast in Terry Zwigoff's black comedy Ghost World (2001),