[12] His father, P. Subramaniam (died 2023[13]), is from a Palakkad Iyer family from Kerala[14][15][16] and his mother, Mohini, is a Sindhi from Kolkata, West Bengal.

[19] Through a family friend who worked with the Enfield company, Ajith was able to get a job as an apprentice and spent six months training to be a mechanic.

[20] He later quit the role at the insistence of his father, who wanted Ajith to have a white-collar job, and joined another family friend's garment exporting company as an apprentice.

He eventually progressed to become a business developer and regularly travelled throughout the country on sales assignments, improving his English-speaking skills.

[22] As a result, his first major theatrical release was the Tamil romantic drama Amaravathi (1993), which Ajith had signed after being recommended to director Selva by Balasubrahmanyam, who had seen parts of Prema Pusthakam prior to its delay.

The film, directed by Vasanth and produced by Mani Ratnam featured him in the lead role opposite Suvalakshmi, whose brother-in-law lusts for her.

Describing the period as a "cruel time", Ajith also continued to have chronic back injuries and several of his other film commitments had become delayed.

[19] Ajith returned in 1998 with another big, successful project in Saran's Kaadhal Mannan, an action romantic comedy, setting the foundation for an expanding fan base.

[30] Ajith's next films Aval Varuvala and Unnidathil Ennai Koduthen also became successes, with the former pairing him with Simran for the first time and the latter featuring him in a guest role alongside Karthik.

[32] The two following roles in the drama films Anandha Poongatre and Nee Varuvai Ena also brought Ajith plaudits for his portrayals.

Amarkalam told the story of a neglected child who grew up and failed to show feelings of love and affection, becoming a gangster in the process, with Ajith's depiction of his rogue character appreciated by critics.

The film featured Ajith alongside prominent actors Mammooty and Abbas and actresses Tabu and Aishwarya Rai.

Dheena, co-starring Laila and Suresh Gopi, released at Pongal and marked the beginning of a new image of Ajith as an action hero who would appeal to the masses.

[citation needed] The year ended off with a brief appearance in Santosh Sivan's Hindi project Asoka, in which Ajith played as one of the antagonist against Shah Rukh Khan, which did not perform well.

[43] In 2002, Ajith appeared in three films, the first two, Red[44] and Raja[45] being box office disappointments, the former further building up his image as an action hero.

The third film Villain, directed by K. S. Ravikumar, portrayed Ajith in a dual role, one as a mentally disabled person and another as a caring brother.

[citation needed] The film saw Ajith portray a dual role, with a song "Thala Deepavali", penned to promote his action image.

During 2006, Ajith returned from his hiatus by appearing in P. Vasu's Paramasivan for which he had lost twenty kilograms to portray the lead role.

[53] Critics from The Hindu stated that Ajith looked "trim and taut" in the film with "only his eyes seeming to have lost some of its sparkle", following the major weight loss.

After Billa, Ajith appeared in the film, Ayngaran International's production Aegan, directed by choreographer Raju Sundaram.

The film, a remake of the 2004 Hindi comedy Main Hoon Na, received mixed reviews and was a failure at the box office.

[62] After a second foray into motor racing, Ajith signed a film directed by Venkat Prabhu, titled Mankatha, which notably became his 50th project.

[citation needed] The film featured him in a full-length negative role as Vinayak Mahadevan, a suspended police officer with a lust for money.

[70] He starred in Vishnuvardhan's Arrambam, alongside Arya, Nayantara and Taapsee Pannu, which was released on 31 October, and earned positive reviews from both critics and audience.

His next film was Veeram, directed by Siva and co-starring Tamannaah, which was released on Pongal 2014,[72] which also earned positive reviews from critics.

[citation needed] His latest project is Vivegam which received mixed-to-negative reviews with critics citing illogical scenes and average screenplay.

[29] Ajith created the non-profit organisation "Mohini-Mani Foundation", named after his parents, in order to promote self-hygiene and civic consciousness and to help ease the problems of urban sprawl.

[84] Besides his acting career, Ajith is also an occasional racing driver, competing in circuits around India in places such as Mumbai, Chennai and Delhi.

[86] The decision to be involved in the sport was made after Ajith's film directed by Gautham Vasudev Menon was delayed, allowing him to participate in the whole season.

Further trials in Sepang, Malaysia followed suit as he practised for the season's beginning in April 2010 in his Formula Renault V6 car with Eurasian Racing, shedding 11 kilograms during training.