He was next seen as the main lead in Agathiyan's epistolary Kadhal Kottai (1996), a critical and commercial success. In 1997, he had five releases, all of which were commercial failures. Ajith's dual portrayal of twin brothers—where one is deaf-mute—in S. J. Suryah's Vaalee (1999) won him his first Filmfare Award for Best Tamil Actor. Impressed with his performance in that film, Rajiv Menon cast Ajith in the ensemble drama Kandukondain Kandukondain (2000) which was also commercial and critical success. The following year, he collaborated with debutant director AR Murugadoss on the action film Dheena. The film was successful in establishing his reputation as an action hero and earning him the nickname "Thala" ("head"). He earned critical acclaim for his dual role performance in the vigilante film Citizen (2001), and the film was commercial success. and a Best Actor nomination at Filmfare for the drama Poovellam Un Vasam (2001). His last release of the year was Santosh Sivan's Hindi film Aśoka, where he played a brief antagonistic role opposite Shah Rukh Khan. His dual-role performance as twin brothers in K. S. Ravikumar's film Villain (2002) won him a second Filmfare Award for Best Tamil Actor.
