While training at the institute, Kapoor was cast as the lead in Rakesh Roshan's Kaho Naa... Pyaar Hai (2000) opposite his son, Hrithik Roshan.
Several days into the filming, however, she abandoned the project; Kapoor later explained that she had benefited by not doing the film since more prominence was given to the director's son.
She debuted later that year alongside Abhishek Bachchan in J. P. Dutta's war drama Refugee.
Set during the Indo-Pakistani war of 1971, Kapoor was introduced as Naaz, a Bangladeshi girl with whom Bachchan's character falls in love.
Dutta cast her for the combination of youthfulness and innocence he found in her, and Kapoor considered their collaboration to be an important learning experience that helped her personally and professionally.
Writing for the entertainment portal Bollywood Hungama, critic Taran Adarsh described Kapoor as "a natural performer" and noted "the ease with which she emotes the most difficult of scenes", and India Today reported that she belonged to a new breed of Hindi film actors that breaks away from character stereotypes.
Refugee was a moderate box-office success in India and Kapoor's performance earned her the Filmfare Award for Best Female Debut.

For her second release, Kapoor was paired opposite Tusshar Kapoor in Satish Kaushik's box-office hit Mujhe Kucch Kehna Hai (2001).
A review in The Hindu noted that based on her first two films, she was "definitely the actress to watch out for".
She next starred alongside Jackie Shroff and Hrithik Roshan in Subhash Ghai's flop Yaadein, followed by Abbas-Mustan's moderately successful thriller Ajnabee, co-starring Akshay Kumar, Bobby Deol and Bipasha Basu.
Later that year, she appeared in Santosh Sivan's period epic Aśoka, a partly fictionalised account of the life of the Indian emperor of the same name.
Featured opposite Shah Rukh Khan, Kapoor found herself challenged playing the complex personality of her character Kaurwaki (a Kalingan princess) with whom Ashoka falls in love.
Aśoka was screened at the Venice and 2001 Toronto International Film Festivals, and received generally positive reviews internationally but failed to do well in India, which was attributed by critics to the way Ashoka was portrayed.
Jeff Vice of The Deseret News described Kapoor as "riveting" and commended her screen presence.
Rediff.com, however, was more critical concluding that her presence in the film was primarily used for aesthetic purposes.
At the 47th Filmfare Awards, Aśoka was nominated for five awards including a Best Actress nomination for Kapoor.

A key point in Kapoor's career came when she was cast by Karan Johar as Pooja ("Poo", a good-natured, superficial girl) in the 2001 melodrama Kabhi Khushi Kabhie Gham... alongside an ensemble cast.
She found little resemblance between herself and her "over-the-top" character, and modeled Poo's personality on that of Johar.
Filming the big-budget production was a new experience for Kapoor, and she recalls it fondly: "[I]t was great fun doing [the film and] we had a blast. [
W]orking with the unit and the six mega star set was a dream come true."
Kabhi Khushi Kabhie Gham... was an immensely popular release, finishing as India's second highest-grossing film of the year and Kapoor's highest-grossing film to that point.
It also became one of the biggest Bollywood success of all time in the overseas market, earning over ₹1 billion (US$14 million) worldwide.
Taran Adarsh described Kapoor as "one of the main highlights of the film", and she received her second Filmfare nomination for the role—her first for Best Supporting Actress—as well as nominations at the International Indian Academy (IIFA) and Screen Awards.

Box Office India reported that the success of Mujhe Kucch Kehna Hai and Kabhi Khushi Kabhie Gham... established Kapoor as a leading actress of Hindi cinema, and Rediff.com published that with Aśoka she had become the highest-paid Indian actress to that point earning ₹15 million (US$210,000) per film.
During 2002 and 2003, Kapoor continued to work in a number of projects but experienced a setback.
All
While training at the institute, Kapoor was cast as the lead in Rakesh Roshan's Kaho Naa... Pyaar Hai (2000) opposite his son, Hrithik Roshan. Several days into the filming, however, she abandoned the project; Kapoor later explained that she had benefited by not doing the film since more prominence was given to the director's son. She debuted later that year alongside Abhishek Bachchan in J. P. Dutta's war drama Refugee. Set during the Indo-Pakistani war of 1971, Kapoor was introduced as Naaz, a Bangladeshi girl with whom Bachchan's character falls in love. Dutta cast her for the combination of youthfulness and innocence he found in her, and Kapoor considered their collaboration to be an important learning experience that helped her personally and professionally. Writing for the entertainment portal Bollywood Hungama, critic Taran Adarsh described Kapoor as "a natural performer" and noted "the ease with which she emotes the most difficult of scenes", and India Today reported that she belonged to a new breed of Hindi film actors that breaks away from character stereotypes. Refugee was a moderate box-office success in India and Kapoor's performance earned her the Filmfare Award for Best Female Debut.
For her second release, Kapoor was paired opposite Tusshar Kapoor in Satish Kaushik's box-office hit Mujhe Kucch Kehna Hai (2001). A review in The Hindu noted that based on her first two films, she was "definitely the actress to watch out for". She next starred alongside Jackie Shroff and Hrithik Roshan in Subhash Ghai's flop Yaadein, followed by Abbas-Mustan's moderately successful thriller Ajnabee, co-starring Akshay Kumar, Bobby Deol and Bipasha Basu. Later that year, she appeared in Santosh Sivan's period epic Aśoka, a partly fictionalised account of the life of the Indian emperor of the same name. Featured opposite Shah Rukh Khan, Kapoor found herself challenged playing the complex personality of her character Kaurwaki (a Kalingan princess) with whom Ashoka falls in love. Aśoka was screened at the Venice and 2001 Toronto International Film Festivals, and received generally positive reviews internationally but failed to do well in India, which was attributed by critics to the way Ashoka was portrayed. Jeff Vice of The Deseret News described Kapoor as "riveting" and commended her screen presence. Rediff.com, however, was more critical concluding that her presence in the film was primarily used for aesthetic purposes. At the 47th Filmfare Awards, Aśoka was nominated for five awards including a Best Actress nomination for Kapoor.
A key point in Kapoor's career came when she was cast by Karan Johar as Pooja ("Poo", a good-natured, superficial girl) in the 2001 melodrama Kabhi Khushi Kabhie Gham... alongside an ensemble cast. She found little resemblance between herself and her "over-the-top" character, and modeled Poo's personality on that of Johar. Filming the big-budget production was a new experience for Kapoor, and she recalls it fondly: "[I]t was great fun doing [the film and] we had a blast. [W]orking with the unit and the six mega star set was a dream come true." Kabhi Khushi Kabhie Gham... was an immensely popular release, finishing as India's second highest-grossing film of the year and Kapoor's highest-grossing film to that point. It also became one of the biggest Bollywood success of all time in the overseas market, earning over ₹1 billion (US$14 million) worldwide. Taran Adarsh described Kapoor as "one of the main highlights of the film", and she received her second Filmfare nomination for the role—her first for Best Supporting Actress—as well as nominations at the International Indian Academy (IIFA) and Screen Awards.
Box Office India reported that the success of Mujhe Kucch Kehna Hai and Kabhi Khushi Kabhie Gham... established Kapoor as a leading actress of Hindi cinema, and Rediff.com published that with Aśoka she had become the highest-paid Indian actress to that point earning ₹15 million (US$210,000) per film. During 2002 and 2003, Kapoor continued to work in a number of projects but experienced a setback. All
Kareena Kapoor