Silambarasan studied at the Don Bosco Matriculation Higher Secondary School.

Simbu began his career by playing roles as a child artist in films directed by his father T. Rajendar, before his first lead role in Kadhal Azhivathillai (2002), under his father's direction and produced by his mother Usha.

Simbu further acted in his father`s movies, including Thai Thangai Paasam, Oru Vasantha Geetham, En Thangai Kalyani, Enga Veetu Velan, Monisha En Monalisa, Oru Thayin Sabhatham, Samsara Sangeetham, Shanti Enathu Shanti, Pettredutha Pillai, Thiruvalla and Sabash Babu.

Silambarasan played his first protaginist role in Kadhal Azhivathillai (2002), directed by his father.

In Thotti Jaya, Silambarasan played the role of an orphaned gangster who finds love. This movie was described by the critics as realistic.

In 2006, he starred in Saravana, directed by K. S. Ravikumar. This was the second time that Simbu and Jyothika worked together after the success of Manmadhan (2004).

Simbu starred in and directed Vallavan (2006), as well as writing its story, screenplay and co-dialogue.

In 2008, he starred in the action masala film Kaalai, which was a flop. Later that year, he appeared in another action masala film Silambattam. The film opened to mixed reviews but became a commercial success.

In 2010, his film Vinnaithaandi Varuvaayaa, directed and written by Gautham Menon, became a Tamil 'cult classic' film. Director K. Balachander in an open letter called Silambarasan's performance as his best in his career.

Silambarasan has been the subject of several controversies, primarily due to his outspoken nature.

Silambarasan has regularly had differences of opinions with fellow actors in the Tamil film industry. He has had a long-running rivalry with actor Dhanush, which has been widely reported in the media.