Singham opens with an honest police officer in Goa, Rakesh Kadam (Sudhanshu Pandey), committing suicide because of false accusations of corruption filed by Jaikant Shikre (Prakash Raj), a don and politician in Goa running various rackets like kidnapping, extortion and smuggling. Kadam's wife Megha Kadam (Sonali Kulkarni) vows revenge but cannot find any support or help from the police or Minister Anant Narwekar (Anant Jog).

The story moves to Shivgarh, a small village near the Goa-Maharashtra border. Bajirao Singham (Ajay Devgn), an honest Maratha police inspector like Kadam, is in charge of the Shivgarh police station. He resolves most of the problems in his town informally and without filing charge sheets, thereby gaining much reputation and love from the villagers. Gautam Bhosle a.k.a. Gotya (Sachin Khedekar) is an industrialist and a friend of Singham’s father Manikrao Singham (Govind Namdeo). He comes to Shivgarh with his wife and daughter Kavya (Kajal Aggarwal). Eventually, Singham and Kavya fall in love with each other. Their courtship takes place through a series of comic events where she initially hates him and then has a change of heart when she sees his honest and simple nature.

Everything seems to run smoothly until Jaikant, who is given a conditional bail for a murder he had committed, is required to travel to Shivgarh to sign the bail every fortnight. He, instead, sends one of his allies to do the formalities, much to the fury of Singham who demands Jaikant sign the bail in person. Humiliated, Jaikant reaches Shivgarh but is unable to take any revenge on Singham fearing the wrath of villagers, who threaten to finish him off. Using his political contacts, he gets Singham transferred to Goa to take revenge.

Singham, unaware of Jaikant’s hand behind his transfer, joins Colva police station. His co-workers, Sub-Inspector Dev Phadnis (Vineet Sharma), Sub-Inspector Abbas Malik (Ankur Nayyar), Head Constable Savalkar (Ashok Saraf) hate Jaikant for his crimes but are unable to take any action because of Jaikant’s political powers. DSP Patkar (Murli Sharma), Singham's senior, is on Jaikant's payroll and takes care in concealing and eliminating the evidence of Jaikant’s crime from the eyes of the law. Singham tries to take this to the notice of DGP Vikram Pawar (Pradeep Velankar)) but it turns out to be of no use as there is no evidence against Jaikant and Patkar. The local minister Anant Narvekar (Anant Jog) does not help Singham and in turn, he warns him to stay away from Jaikant's case. Defeated Singham wants to return to his hometown but is stopped by Kavya and Megha Kadam, who encourage him to fight against the evil and not run away like a coward.

Being mentally tortured by Jaikant, Singham arrests Jaikant's top lieutenant Shiva Nayak (Ashok Samarth) in a fake case of illegally smuggling alcohol. He thwarts off DSP Patkar in full view of the public when Patkar, bounded by his duties to Jaikant, tries to protect Shiva. Meanwhile, Megha Kadam, after being ridiculed by DGP Pawar and minister Narvekar for her innocent husband’s death, seeks help from Singham to absolve her late husband from the corruption charges. Jaikant kidnaps Kavya’s younger sister Anjali (Sana Amin Sheikh) for ransom. Rescuing her, Singham successfully traces the origins of the kidnapping racket to Jaikant but is unable to arrest him as he wins an election and is set to become a minister of Goa Govt.

Jaikant sends transfer orders to Singham to go back to Shivgarh within 24 hours. That night at a police function organized for the officers with their family, Singham confronts the officers for not abiding by their duties and being dishonest and unfaithful to their profession by protecting Jaikant. At first, the officers disagree with Singham, but filled with guilt, the officers decide to help Singham fight Jaikant. Soon, the entire Goa Police Force reach his home to kill him, with DGP Pawar and DSP Patkar, now in support of Singham. Jaikant eventually escapes but after running through the city, he is arrested by the police the next morning. They bring him to the police station and shoot him dead on the same chair where Inspector Rakesh Kadam had shot himself. Then they threaten Shiva to change his statement. Jaikant and Minister Narvekar are proved guilty. At a media conference, DGP Pawar and Singham clear late Kadam of all corruption charges.

The film ends with Singham and other police officers saluting Mrs.Megha Kadam.

After the success of the Tamil film Singam, directed by Hari in 2010, the film's remake rights were sold by the producers for Hindi and Kannada versions. The co-producers of the Tamil version, Reliance Big Pictures purchased the Hindi remake rights and announced in November 2010 that the version would feature Rohit Shetty as director and Ajay Devgn in the lead role. Prakash Raj was signed on to reprise his role as the antagonist from the original, whilst reports emerged that Asin and Anushka Shetty were being considered for the female lead role.

In mid-February 2011, Kajal Aggarwal, an actress who predominantly features in South Indian films was signed in as the female lead.

Singham went on floors in November 2010, with its scheduled cast. The first schedule began in early March 2011 with action sequences shot in Goa featuring technicians from South India.

A scene with Prakash Raj and Ajay Devgn was shot in Goregaon in Mumbai with around 500 junior artists as villagers. Another scene was shot at Vagator in Goa for which 100 police jeeps were called. The shooting was stalled by the Federation of Western India Cine Employees (FWICE) members who demanded ?45 lakh to be paid to the workers when it was being shot in Film City in Mumbai.

Reliance Entertainment released Singham on 22 July 2011 in 2000 screens worldwide with 1500 prints excluding overseas.
The film's DVD was released on 23 August 2011. The Delhi High Court, upon Reliance Entertainment's request, issued an order to all Indian ISPs to block file sharing sites to prevent unauthorized sharing of Singham.

Critical reception

The film met with positive to average reviews. Based on 93 reviews, review aggregate site desimartini.com gave the film the verdict, "A shout out to yesteryear masala movies, Singham is an out and out action entertainer with Ajay Devgan reminding us of his old action films, while Prakash Raj gives another solid performance. If masala movies amuse you, go for it!" The site's average audience rating is 3.0/5.

Nikhat Kazmi of The Times of India gave it four out of five stars and stated "Singham is over-the-top retro kitsch, spilling over with high-voltage stunts, slow-motion action cuts and fiery dialogues delivered in high decibels. It is meant for all those action buffs interested in time travel to the angry young 1970s and 1980s when cinema was larger-than-life and totally unrealistic. But then, retro is currently chic, isn't it?" Komal Nahta of Koimoi gave it four and a half stars out of five stars and said "On the whole, Singham is a powerful action-emotional drama which boasts of equally powerful dialogues and absolutely power-packed performances. It’s a super-hit and will be loved by the masses and the classes, the men and the women, the young and the old, the rich and the poor. It is the kind of film which consumes the viewer and gives him the feeling that he was part of the fight against corruption! The film has immense repeat-value. Its business in Maharashtra will get a further boost because of the liberal use of Marathi in the dialogues. Kaajal Aggarwal acts with effortless ease. Her performance is good."
Suparna Sharma of The Asian Age gave it two out of five stars and stated "Singham is a primitive, archetypal genre piece, and it is a hit. Rohit Shetty taps into the sentiment of the moment – emasculation, frustration – and gratifies it. But endowing a cop with nobility doesn’t ring true, especially not when he is neither Chulbul-charming nor when the target of his anger and lashing is generic sleaze… Singham is vigilante cop let loose on all things foul. I felt fluctuating connect with Singham, but mostly he made me queasy." Taran Adarsh of Bollywood Hungama gave the four and a half stars out of five and said "Singham pays homage to the action films of the 1970s, which was known for the heroism, death-defying action sequences and pulse-pounding thrills. It's an acknowledgement to one of the most successful genres of Bollywood – action movies – known for the trademark good versus evil themes and well choreographed stunts." Saibal Chatterjee from NDTV also gave four out of five stars and said "Singham is an old-fashioned but rousing Hindi commercial film that pretty much restores one’s faith in this often-maligned brand of cinema. It has super-duper hit written all over it. No matter how dismissive you might be of films that have no space for shades of grey, chances are that Singham will disarm you, if only for a bit." Dailybhaskar gave a score of three stars out of five and said "The action takes over the romance in the film. Go for it, if you want to catch one hell of an action flick! "

Sukanya Venkatraghavan from Filmfare gave two stars out of five and said "Singham is a film that will invoke wolf whistles and applause from its audience. It is gloriously massy. The movie knows its job and does it well. It does nothing out of the box to grab your attention and yet it does. Pretty easily. Watch it for its robust potboiler personality. With extra masala as garnish. Ajay Devgan pulls out all stops for this one. He is fierce and impactful. This is his show all the wa