Durai Singam (Suriya) is the honest police sub-inspector of Nallur, a small village in Thoothukudi district in southern Tamil Nadu, assisted by his bumbling colleague Erimalai (Vivek). He belongs to Nallur with his father, Soundara Pandi (Radha Ravi) having a respectable status in the village. His family business is provision stores and Durai Singam wants to join it, but he joined police due to Soundara Pandi's wishes. He resolves most of the problems in his village with non-violence and mutual counselling. He uses force only when the situation demands it, thereby gaining much reputation and love from the villagers. Mahalingam (Nassar), an industrialist in Chennai and a friend of Soundara Pandi, comes to the village with his daughter Kavya (Anushka Shetty). Durai Singam initially mistakens Kavya as a thief (when she is about to prank her cousin by wearing a tiger costume and roam around the village), accidentally slaps her. As Kavya is about to take revenge on Singam, he apologizes to her, Kavya got moved, slowly fell in love with him. After some hilarious incidents, Kavya proposes to Durai Singam. Initially taken aback, soon Durai Singam reciprocates Kavya's love.
Chennai-based Mayil Vaaganam (Prakash Raj), a big-time extortionist with shady mafia dealings who blackmails people by complaining to the Income Tax Department, is required to travel to Nallur to sign a conditional bail. He instead, sends one of his allies to do the formalities, much to the anger and rage of Durai Singam who demands Mayil sign the bail in person. Humiliated, Mayil reaches Nallur but is unable to take any revenge on Durai Singam fearing the immense love and devotion of the entire village towards Durai Singam. Using his political contacts, he gets Durai Singam transferred to Chennai to teach him a lesson.
Durai Singam, unaware of Mayil's hand behind his transfer, joins Thiruvanmiyur police station. His co-worker, Sub-Inspector Ravi (Bose Venkat), hates Mayil for his crimes but is unable to take any action because of Mayil's political powers. The Assistant Commissioner of Police, Rajendran (Nizhalgal Ravi), Durai Singam's senior, is on Mayil's payroll and takes care in concealing and eliminating the evidence of Mayil's crimes from the eyes of the law. The Police Commissioner (Ajay Rathnam) also does not help Durai Singam as there is no evidence against Mayil and Rajendran and in turn, warns him to stay away from Mayil's case. Unable to take on Mayil in his stronghold, Durai Singam wants to return to his village but is stopped by Kavya who encourages him to fight against the evil and not run like a coward.
Being mentally tortured by Mayil, Durai Singam arrests Mayil's brother Vaikundam (Adithya Menon) in a fake case of illegally smuggling alcohol. He thwarts off Rajendran in full view of the public when Rajendran, bounded by his duties to Mayil, tries to protect the henchman. Meanwhile, Mayil kidnaps Kavya's younger sister for ransom. Rescuing her, with unexpected help from the Home Minister, Ramanathan (Vijayakumar). Durai Singam successfully traces the origins of the kidnapping racket to Mayil. Durai Singam also gets promoted to Assistant Commissioner of the specially-formed Anti-Kidnapping Task Force. Mahalingam, who was hostile to Durai Singam following an altercation with Soundara Pandi back at Nallur, softens up and agrees to give him Kavya's hand in marriage.
The police officers, including the Police Commissioner, and Rajendran, now on Durai Singam's side, decide to help Durai Singam fight Mayil. They manage to kill Mayil's henchman in an encounter at a hospital and begins to target everyone and everything related to Mayil. In retribution, Mayil starts targeting everyone close to Durai Singam, including Kavya, whom he shoots but is saved by Durai Singam, and Ravi, who is hacked to death by Mayil's henchmen. To escape the arrest warrant issued out to him, Mayil kidnaps the Karnataka Home Minister's daughter. He falsely tells Durai Singam that he is going to Pondicherry with her when actually he is going to Nellore in Andhra Pradesh to put the police off the track. However Durai Singam manages to pursue them till Gudur near Nellore, where he rescues the home minister's daughter and kills Mayil in an encounter.
During the credits, Durai Singam is seen with Kavya heading back to Nallur, and as when Durai Singam is stopped briefly by Ramanathan who offers an undercover mission, to which Durai Singam willingly agrees.
After Suriya had finished K. S. Ravikumar's adhavan, discussions regarding his subsequent project, notably his 25th film, were held. Initially, reports emerged that it was going to be directed by Prabhu Deva. At the launch of his film Seval in May 2009, however, director Hari announced officially that he would direct Suriya's 25th film titled Singam and that he had finished penning the script. Becoming Suriya's third film with Hari following Aaru and Vel, it was announced that the project would release in July 2010. Suriya's cousin, K. E. Gnanavel Raja was announced as the producer.
Though initial reports suggested that Yuvan Shankar Raja would score the music, Devi Sri Prasad was chosen as the music director, thus becoming his third venture with Suriya. Suriya was revealed to play a police officer in the film, the second time in his career after Kaakha Kaakha. Anushka was chosen to play the female lead, after several actresses were considered and approached. Priyan was chosen as the lead camera man and V.T. Vijayan as the editor.
After completing Seval, Hari joined the cast and crew to start the filming in 2009. The shooting began in Thirunelveli district and was carried on in southern parts of Tamil Nadu. A scene from the song "Stole my Heart" was shot in Muscat Park that was choreographed by Brindha. Afterwards, some scenes where shot in Karnataka. The main scenes were shot in Thiruvanmiyur, Chennai. During December, Hari announced that the film wouldn't have a formal audio launch as per his previous films and that the shooting would get over quickly. The trailers were released on 24 February. Sun Pictures acquired the distribution rights, and Sony Music bought the music for a hefty price.
The film's soundtrack, released on 11 May 2010, was scored by Devi Sri Prasad, marking his third collaboration with Suriya after Maayavi and Aaru.
The satellite rights of the film were secured by Sun TV. The film was given a "U/A" certificate by the Indian Censor Board and released worldwide on 28 May 2010 released in 850 screens worldwide. Telugu dubbed version titled Yamudu released on 2 July 2010.
Behindwoods gave 2.5 out of 5 and stated that Hari has "concocted and packaged his masala contents in the right proportion and has served a tasty dish", while praising Suriya for having "diligently worked towards balancing the niche and the mass" and proving "once again that he can deliver a commercial masala flick with as finesse as he can deliver a performance-oriented film". Sify described the film as a "predictable entertainer that follows the age old formula", citing that it was Suriya who "carries the film to the winning post. His passion and the way he brings an ordinary regular larger-than-life hero character alive on screen is lesson for other commercial heroes". Rediff also gave 2.5 out of 5 stating that the film was an "unapologetic, entertainer and has Suriya in every frame. Lovers of commercial potpourri will definitely get their money's worth." Indiaglitz wrote that Singam was the "king of the masses, who love action and commercial films". A Times of India critic gave 3.5 out of 5, claiming that "even with a sleepy narration in the first 30 minutes or so, Singam is worth a watch."
Singam was the third highest grossing Tamil film of the year with collecting more than Rs. 5.38 crores in Chennai. In Malaysia, the film collected $1,471,508 and $12,956 in United Kingdom.
Singam was remade in three different languages.Best Dance Choreographer – Baba Bhaskar for "Kadhal Vandhale"