Kajal made her acting debut with the 2004 Bollywood film Kyun…! Ho Gaya Na and had her first Telugu film release in 2007 Lakshmi Kalyanam. In the same year, she starred in the box office hit Chandamama, which earned her critical acclaim. She subsequently earned wide critical recognition for her Dual portrayal in 2009 historical fiction Telugu film Magadheera. The film rank among the highest-grossing Telugu films of all time and fetched her Best Actress nominations at several award ceremonies including Filmfare. She followed with a series of box-office hits in Telugu and established herself as one of the leading and highest-paid actresses in Tollywood.
Kajal achieved further success by featuring as the female lead in the high-profile Tamil projects Maattrraan (2012), Thuppakki (2012), Jilla (2014) and emerged as a leading actress in Tamil cinema as well. She made a comeback to Bollywood with Singham (2011) which was a blockbuster while her next film Special 26 (2013) was also declared a box-office success.