Based on the incidents from the Operation Bawaria case, it depicts the nefarious activity of dacoits and its eventual containment with the Tamil Nadu Police squad headlined by DGP S. R. Jangid.

The film, distributed and co-produced by Reliance Entertainment, was released worldwide on 17 November 2017 and opened to critical acclaim, praising the direction, writing, cinematography, soundtrack, musical score, and the cast performances—especially that of Karthi.

Theeran tops the training period and returns to his hometown of Tanjavur, where he falls in love with his new neighbor Sripriya alias Priya, and the two happily get married.

Simultaneously, a group of dacoits wrecks a house, situated along the highway of Tamil Nadu, where they barge and kill all the people inside gruesomely and takes their belongings.

[3] He stated that he had the idea of making a film on the case before he made Sathuranga Vettai but had forgotten about it until he opened a food parcel, which was coincidentally covered with a newspaper article narrating the events of the operation and the incident subsequently inspired him to work on the script.

[4][5] Initially, planned as a road-trip film, the script was later evolved into a full-fledged police story revolving around the entire timelines of the operation and the events happened.

The film talks about an officer’s personal journey, the shortcomings in the system and what our status is when we go out of Tamil Nadu — our comfort zone and how we are viewed.

[7] Vinoth continued to script the film throughout the year, while Karthi finished his pending work for Kaashmora (2016) and Mani Ratnam's Kaatru Veliyidai (2017).

[4] Karthi plays the titular character Theeran, modelled on the Tamil Nadu Director General of Police S. R. Jangid, who led a special team to track down the main criminals involved in dacoity as a part of the Operation Bawaria case.

[15] Bose Venkat was also selected to portray a police officer in the film, with the actor stating that the role gave him "a new dimension and a new identity".

[25] To make the film as authentic as possible, Vinoth actively hired artistes from the regions and insisted on shooting in such locations, rather than replicating the terrains in Chennai or in studios.

[28][6] On filming a chase scene involving two buses on a highway in Bhuj, Karthi said that "the exposure to the harsh sunlight became unbearable that he was literally under the verge of developing sun stroke".

[31] In April 2017, an item number featuring actress Scarlett Mellish Wilson at Jaisalmer Fort in Rajasthan, with the song being choreographed by Brindha.

Jayachandran used the painting style for one portion and a graphic novel approach for the pre-interval sequence, with the primary use of colors — black, white and red — since blood was the theme of the film.

[38] Speaking about the use of animation, Vinoth said that "the scenes might feel difficult in production as it required the historical approach and further more it featured excessive violence sequences, that may result in huge cuts when it comes to censors.

Armed dacoits had struck affluent houses along National Highways in Tamil Nadu, Karnataka and Andhra Pradesh in the late 1990s and early 2000s.

"[62] The producers further stated that the controversial scene and the word used to describe the community will not be included in theatres, television broadcast and official online streaming portal.

"[73] Srinivasa Ramanujan of The Hindu stated it as "an engrossing cop film that keeps you glued to the screen every moment" and further wrote "There’s sincerity in the writing and research and honesty in the performances.

"[75] Baradwaj Rangan of Film Companion South wrote "There are plenty of sharp, funny lines, and the highlights keep coming, like a superbly choreographed action stretch on a bus.

"[76] Ashameera Aiyyappan of The Indian Express said that "the film delivers what it promises and packs quite a neat punch in most places" and gave three out of five stars.

The only commercial compromise Vinoth has made is to have a romantic plot for the hero for the regular family moments, comedy and background songs.

[82] Calling it as "one of the best films of the year", Indiaglitz said that "If Vinoth's Sathuranga Vettai is one of the most authentic deconstruction of heist and deception crimes Theeran is the same for police procedure.

Like how he posts a salute to the true cops who cracked the crimes in real life he deserves one for his painstaking research, authentic narration and plain honest hard work".

[84] Sowmya Rajendran of The News Minute said "Theeran is a cop film entirely from the perspective of law enforcers and that makes its politics troubling.

Nevertheless, given that we've had a slew of films in this genre in recent times (including the now-getting-stale Singam series), its triumph lies in managing to pull off something fresh and original.

The love angle is wholly dispensable, regardless of what Theeran’s manipulative voice-over will make you believe, and also by the inclusion of disappointing elements like the outdated villain-item-number.

[71] Contrarily, the film garnered criticism towards the negative stereotyping of tribal and nomadic communities, albeit the producers' explanation post-release.

[109] An article from Hindustan Times, written by Gayatri Jayaraman dated October 2018, highlighted how nomadic communities ended up bearing the brunt of fictional fear mongering,[109] citing the examples of Adivasi youth being beaten to death by mob in Palakkad on February, and the killing of a 65-year old woman at Tiruvannamalai;[110][111] she said that the film "capitalised on this dissimilarity to stir the them-versus-us sentiment and to portray the outsiders as villains and thugs.

"[109] In January 2023, Vinoth recalled that he felt guilty on the depiction of North Indians in the film, and this led him to sketch the protagonist in Valimai, where he was seen speaking against encounters and drugs.

[113] On 17 November 2023, the sixth anniversary of the film, Vinoth confirmed that he had begun working on the sequel and is expected to begin production in early 2025.