In the start of 2009, he acted in the film 1977, donning six different looks. The film, made with a whopping budget of 15 crores, was directed and produced by newcomer G. N. Dinesh Kumar. The film, which released to negative reviews, took an average opening and was declared a flop at the box office. In October 2009, Sarath Kumar made his debut in Malayalam through Pazhassi Raja, in which he co-starred with Mammootty and he played the role of Edachena Kunkan. The film, directed by Hariharan, became the highest-grossing film of the year in the Malayalam industry and Sarath Kumar won the Vanitha Film Awards for Best Supporting Actor. After the success of Pazhassi Raja, Sarath Kumar was flooded with offers in Malayalam. Jaggubhai was released on 29 January 2010, the film, directed by K. S. Ravikumar, became the tenth collaboration between the Director and the actor. The film, facing serious piracy problems before its release, bombed ultimately at the box office. He then made a guest appearance in Madhumitha's comedy film Kola Kolaya Mundhirika. In the end of 2010, he acted in the Malayalam film Oridathoru Postman, which was a flop at the box office. In early 2010, he acted in his first Malayalam film The Metro as a solo hero, which bombed at the Kerala box office. He appeared in Christian Brothers, directed by Joshiy, starring alongside Mohanlal, Dileep, and Suresh Gopi. The film was a blockbuster. In mid-2011, Sarath Kumar played the role of a transgender person in Raghava Lawrence's Muni 2: Kanchana. The film became a commercial success in both Tamil and Telugu, he won for his performance a Vijay Award for Best Supporting Actor. In early 2012, he accepted Soundarya's offer for an important role in the film Kochadaiiyaan, starring Rajinikanth and Deepika Padukone. He played lead role in the Malayalam film Achante Aanmakkal as an IPS officer. He then starred in his first Kannada film Saarathi, which was a blockbuster, followed by the Telugu film Genius. The next year, he played the role of a police officer in the Kannada film Myna. His next venture was Chennaiyil Oru Naal, a remake of the Malayalam hit film Traffic and co-produced by his wife Raadhika Sarath Kumar, in which he played the role of a traffic police commissioner. The film became a critical and commercial success. He then appeared in the Telugu film Chandee, playing the role of a police officer. In the beginning of 2014, he played the role of a CBI officer in Nimirndhu Nil and Janda Pai Kapiraju, which were shot simultaneously in Tamil and Telugu. He then appeared in "India's first photorealistic performance capture film" Kochadaiiyaan, co-starring Rajinikanth and Deepika Padukone.