Established actress (2002–2006)
Mukerji began collaborating with Yash Raj Films in 2002, when the company cast her in two productions: Mujhse Dosti Karoge!, a romantic comedy co-starring Hrithik Roshan and Kareena Kapoor, and Saathiya, a remake of the Tamil romance Alaipayuthey. The former performed poorly at the box office, as did her two collaborations with Govinda that year—Pyaar Diwana Hota Hai and Chalo Ishq Ladaaye. The romantic drama Saathiya, however, proved a turning point in her career. At the 48th Filmfare Awards, she received her first Best Actress nomination and was awarded the Critics Award for Best Actress (shared with Manisha Koirala in Company). Shaad Ali cast her in the role of Suhani Sharma, a medical student who deals with the troubles of being married at a young age, for the vulnerability that he found in her. She refused the offer at first as she disliked the idea of remaking an accomplished film but was convinced to accept the part by the film's producer Aditya Chopra. In it, she played opposite Vivek Oberoi, with whom she did not enjoy working, saying that his "attitude was bothersome". Saathiya emerged as a commercial success. The BBC wrote that "Mukerji plays the character of a middle-class girl with great conviction", and Udita Jhunjhunwala of Mid-Day added that "her expressions and acting are understated in a role that fits her like a glove".
The year 2003 marked the beginning of the most successful period in Mukerji's career. She replaced Aishwarya Rai to play the lead opposite Shah Rukh Khan in Aziz Mirza's romance Chalte Chalte. Media reports suggested that Rai was replaced after feuding with her then boyfriend Salman Khan on the film's sets, but Shah Rukh Khan insisted that Mukerji had been the original choice for the role. Mukerji believed that the theme of Chalte Chalte, which dealt with misunderstandings between a married couple, was similar to that of Saathiya, and she tried to lend variety to the role by putting "them against a different background". She has said that working with Shah Rukh Khan was a learning experience for her, and he would often scold her if she performed inadequately. A commercial success, Box Office India credited it as a career comeback for Mukerji, and she received her second nomination for the Filmfare Award for Best Actress. None of her other releases of the year—Chori Chori, Calcutta Mail, and LOC: Kargil—made a mark.
At the 50th Filmfare Awards, Mukerji won both the Best Actress and Best Supporting Actress awards, becoming the only actress to win both awards in the same year. The Best Supporting Actress win was for Mani Ratnam's Yuva (2004), a composite film with an ensemble cast, about three youngsters from different strata of society whose lives intersect by a car accident; Mukerji was cast as Shashi Biswas, a poor Bengali housewife who is abused by her husband, a local goon (Abhishek Bachchan). She based her role on her house helps who were abused by their husbands and observed their body language and speaking style. Taran Adarsh wrote, "Amongst the leading ladies, it is Rani Mukerji who is the best of the lot. The role demanded an actress of substance and Rani more than lives up to the expectations." She won the Best Actress award for her starring role as Rhea Prakash in Kunal Kohli's Hum Tum (2004), a romantic comedy about two headstrong individuals who meet at different stages of their lives. The film pitted her opposite Saif Ali Khan and proved one of the biggest commercial successes of the year. The Hindu found Mukerji's portrayal of Rhea
to be "self-assuredly competent" and Tanmaya Kumar Nanda of Rediff.com wrote, "Rani is her usual collected self, changing into the many hues of her character with the ease of a chameleon".
This success continued when Yash Chopra cast her in his period romantic drama Veer-Zaara (2004). Set against the background of India–Pakistan relations, it is about the titular star-crossed lovers (Shah Rukh Khan and Preity Zinta). In a part originally written for a man, Mukerji played a Pakistani lawyer who tries to help the couple. With a worldwide gross of ₹940 million (US$9.8 million), Veer-Zaara emerged as the highest-grossing Hindi film of the year, and it was later screened at the Berlin International Film Festival. Derek Elley of Variety took note of the "quietly dignified perf from Mukerji", and the BBC opined that she "deserves praise for her acting. To act through your eyes and not using dialogue is an art. Rani for one, has perfected this." She won the IIFA Award for Best Supporting Actress, and received her fourth nomination in the same category at Filmfare.
In 2005, Outlook magazine published that Mukerji had established herself as the most successful actress of contemporary Hindi cinema. Her first film role that year was opposite Amitabh Bachchan in Sanjay Leela Bhansali's Black, a drama about an alcoholic man who dedicates his life to teach a blind and deaf girl how to communicate. Bhansali wrote the part of the blind-deaf girl specifically for Mukerji, who was initially hesitant to take on the role due to its "challenging" subject matter. Once Bhansali enforced his faith in her, she agreed and began studying sign language with professionals at the Helen Keller Institute in Mumbai. Black won several awards including two National Film Awards and 11 Filmfare Awards, and Richard Corliss of Time featured it as the fifth best film of the year. Empire magazine called Mukerji's performance "astonishing", and Filmfare included her work in their listing of Indian cinema's "80 Most Iconic performances" and wrote, "Rani has left an indelible mark with this role that usually comes once in a lifetime for most". She became the only actress to win both the Best Actress and Best Actress – Critics trophies at the Filmfare Awards ceremony.
Mukerji received a second Best Actress nomination that year at Filmfare, and her fifth overall, for her work opposite Abhishek Bachchan in Bunty Aur Babli, which marked her fifth collaboration with Yash Raj Films. She played the title character of Babli, a con woman. The film was the second highest-grossing Hindi film of 2005. Namrata Joshi of Outlook wrote that she "plays to the gallery with ease". Mukerji followed it with Amol Palekar's fantasy film Paheli, reuniting her with Shah Rukh Khan. The film was a box office flop in India but was given a strong international release; it was screened at the Sundance Film Festival and was India's submission for the Best Foreign Language Film at the 79th Academy Awards. Raja Sen of Rediff.com was impressed by the film as well as Mukerji's performance which he called "another perfectly played part". Mukerji's final release of the year was the period film Mangal Pandey: The Rising, about the titular soldier. Director Ketan Mehta initially approached her for a cameo appearance, which was developed into a larger part during filming. Her role was that of Heera, a prostitute who becomes the love interest of Pandey (Aamir Khan). Derek Elley mentioned that despite a small role, Mukerji made "the most of her feisty nautch-girl".
Mukerji turned down an offer from Mira Nair to star in the English film The Namesake, choosing instead to reteam with Karan Johar in Kabhi Alvida Naa Kehna (2006), a drama about infidelity. Collaborating once again with Shah Rukh Khan, Abhishek Bachchan and Zinta, she played an unhappily married woman who has an affair with a married man. Commenting on the divisive nature of her role, Mukerji said that it changed her own perception of love and marriage. Kabhi Alvida Naa Kehna was a popular release, earning over ₹1.13 billion (US$12 million) to emerge as the highest-grossing Hindi film in overseas to that point. Rajeev Masand wrote that the "consistently competent Rani Mukherjee takes on the film's toughest role — a part that may be hard to sympathise with — but she injects it with tenderness and believability", but Kaveree Bamzai of India Today dismissed it as another one of her roles requiring the "art of weeping copiously and smiling valiantly". It won Mukerji a third consecutive IIFA Award for Best Actress and a sixth Best Actress nomination at Filmfare. The poorly received melodrama Baabul was her final film appearance of that year.
