The film stars Vikram as the titular character, with Prabhu, Shriya Saran, Ashish Vidyarthi, Mukesh Tiwari, Krishna and Vadivelu appearing in supporting roles.

[4] Kanthaswamy is an officer in the CBI Economic offences Wing, who along with his friends grants the wishes of the needy (whom they write letters in Lord Muruga temple) by disguising as an anthropomorphic rooster behavioured vigilante.

During a CBI raid, Kanthaswamy discovers a stash of black money owned by Pallur Paramajothi Ponnusamy alias PPP, an arrogant business tycoon and his partner Rajmohan.

Ponnusamy's daughter Subbalakshmi gets enraged by the news and goes after Kanthaswamy to seek revenge by pretending to be in love with him.

Knowing her real intentions, Kanthaswamy plays along, which forms a cat-and-mouse chase between the two where they eventually fall in love with each other.

In a parallel comedic role, Thengakadai Thenappan/Kobarikayala Subbayya is also sought by a local police inspector who tries to solve the mystery of "Lord Muruga saving the people".

In a series of twists, the police inspector is able to bring out the truth that the CBI is involved in the role behind the secret work of helping the needy people, though he is not able to confirm it.

In January 2007, early reports suggested that Kalaipuli International were set to make a film starring Vikram directed by Susi Ganesan, titled Kanthaswamy for a release during Diwali 2007.

[16] Prabhu was also added in a supporting role, as well as lesser established actors such as Vikram's father Vinod Raj, Y. G. Mahendran, Shiv, Arun Madhavan, Vinayak and Alex, whilst Mumaith Khan was assigned for an item number.

[18] Indrajith was selected for the role ahead of other prominent character actors Arjun Rampal, Irfan Khan and Suman.

Veterans Thotta Tharani, A. S. Laxmi Narayanan and Viveka between them, take care of the art direction, audiography and lyrics respectively.

Kanthaswamy received mixed reviews from critics, with praise for Vikram and Shriya's performances, the soundtrack, background score, and plot.

[24] Indiaglitz reviewed that "the movie was delight to watch and praised Shriya that as a cool cat, she plays a perfect foil to Vikram in the film".

[26] Rediff gave the film 2.5/5 stars and commented: "Watch Kandhasamy for its beautiful locales, a ravishing heroine, and Vikram's smile but go with nil expectations as this particular super-hero doesn't have much to offer a discerning viewer".

"[30] Idlebrain gave the film a rating of two-and-a-half out of five and noted that "On a whole, Mallana is an example of what happens when popular screenplay goes wrong in any of Shankar's movies".