While working at the Secretariat in Chennai, Vivekh in his free-time participated at the Madras Humour Club where people would perform stand-up comedy. He helped pioneer the movement to expand and subsequently won the Best Entertainer Award several times during his pantomimes at the Club. Vivekh subsequently left Chennai and went on to obtain a bachelor's degree in commerce from Madurai and during semester breaks, he would return and perform at the Club. Through an acquaintance at the Club, P. R. Govindarajan, he was introduced to film director K. Balachandar for the first time and began a professional relationship as a script-writer for the director's films. Vivekh revealed that after four years, Balachandar explained a situation and asked him to write a script for sixteen characters, which Vivek completed over night. He later understood that this was actually a test, and through his performance, Balachandar became closer to Vivek. While assisting with the script for Manathil Uruthi Vendum in 1987, Balachandar offered Vivek an acting role of Suhasini's brother in the film, which he decided to pursue. He began his career portraying supporting roles and collaborated again with Balachandar in Pudhu Pudhu Arthangal (1989) and Oru Veedu Iru Vasal (1990), before often appearing in the primary cast as a friend to the film's lead actor in films such as K. S. Ravikumar's Putham Pudhu Payanam (1991) and Vikraman's Naan Pesa Ninaipathellam (1993). He then also made appearances in Rajinikanth's big budget productions Uzhaippali (1993) and Veera, playing secondary cast roles. Vivek had to wait till 1996 to establish himself as a sole comedian who could help carry the film, and thereafter began to appear in increasingly prominent roles in his ventures.
In the late 1990s, Vivek was able to make a breakthrough by appearing as the lead comedian in films, who would often be the main friend of the lead actor and thus his on-screen time began to increase. He worked consecutively on successful films starring Ajith Kumar, appearing as a sidekick in Kaadhal Mannan, Unnaithedi and Vaali, and had similar success repeatedly featuring alongside Prashanth in Kannedhirey Thondrinal, Poomagal Oorvalam and Aasaiyil Oru Kaditham. He subsequently became amongst the most busy actors in 2000 and 2001, featuring in over fifty films in two years. Films including Kushi, Priyamanavale and Minnale became blockbusters, while his roles in Mani Ratnam's Alaipayuthey, Mugavaree and Dumm Dumm Dumm all won critical acclaim for the actor. The rising success of Vivek's films had meant that he was featured on film posters on an equivalent scale to the lead actor, and thus helped stuck films find distributors. Telugu films were dubbed into Tamil and released with an additional comedy track featuring the actor such as Kanden Seethaiyai, while devotional films such as Kottai Mariamman, Palayathu Amman and Nageswari were released with a separate comedy track featuring Vivek. In 2000, director K. Subash had planned a film starring Vivek in the leading role titled Enakkenna Korachal?, however the film never materialised. Similarly in 2001, he began production on a film titled Panju by Rama Narayanan in which he appeared as the protagonist, but the venture was also then after shelved as was another film to be directed by Sivachandran.
Vivek worked on more commercially successful ventures in 2002 and 2003, receiving consecutive Filmfare Best Comedian Awards and Tamil Nadu State Film Award for Best Comedians for his work. His comedy track in Run won him multiple accolades, with a critic adding Vivek's "nods to current social events showed a stroke of brilliance". He played extended comedy roles in Vikram's Dhool and Priyadarshan's Lesa Lesa, while winning further acclaim for his portrayal of a teacher in Saamy and a software engineer in Parthiban Kanavu. He then played a marginally more serious role in S. Shankar's coming-of-age tale Boys, portraying a mentor to the group of youngsters, and his performance was well received. Critics noted that "Vivek, for a change, follows Shankar’s script and delivers with his impeccable sense of comic timing", while the reviewer from The Hindu claimed that "the show belongs to Vivek, he's the mouthpiece for the director." Success continued in 2004, where he retained the Filmfare Award for Best Comedian for his role of a marriage assembler in Perazhagan, while his roles in Chellamae and M. Kumaran son of Mahalakshmi helped contribute to the films' commercial success respectively. His rising profile as an actor meant that he became the first comedian to become an ambassador for the soft drink, securing the sponsorship deal with Mirinda after the brand had carried out market surveys to find a popular promoter. He also made a special exception to appear in a few artistic films and often charged significantly less remuneration for the ventures, notably playing character roles in Janaki Vishwanathan's Kutty (2001) and Thangar Bachan's Azhagi (2002). In the latter film, the director had requested Vivek to write and appear in a role himself, in order to use his fame to help the film find a distributor for release.
A film which would feature Vivek in the leading role finally materialised in early 2004 and he completed a project titled Solli Addipean directed by newcomer Ramki. The team worked on the production of the film for close to a year and ensured that the audience would be able to accept the comedian's transformation into a lead role, with actresses Chaya Singh and Tejashree cast as the film's heroines. Despite completion, the film has been stuck since 2004 and as a result of a failure to find a distributor, the film is unlikely to have a theatrical release. In mid 2004, he suffered an injury during the production of a film and took a break from acting assignments for a period of six months. He returned by portraying a well-received supporting role in Shankar's Anniyan (2005), appearing as an undercover police officer hunting down clues left by a psychopath serial killer. The film opened to critical and commercial success with a critic noting "Vivek’s comedy is bankable", and the actor subsequently went on to win the State Award for Best Comedian for his work on the venture. He continued his comeback with appearances in Vijay's Aadhi, Ajith Kumar's Paramasivan and Silambarasan's Saravana, all of which released on the same day in January 2006. After winning acclaim for his performance as a comedic undercover detective in Susi Ganesan's Thiruttu Payale, Shankar approached him to feature in a prominent role in his venture Sivaji (2007), starring Rajinikanth, which would go on to become the most expensive Tamil film made at release. Vivek allotted ninety days for the film, significantly more than any of his previous films, and his performance as Rajinikanth's sidekick Arivu, won him another award from the state for Best Comedian. He won positive reviews from critics for his performance, with reviewers noting his "one-liners are really whacky and hilarious" and that "Vivek must come in for special mention for his performance".
In the late 2000s, Vivek's market reach began to falter as a result of changes in screenplay in Tamil cinema, which saw less films adopting a separate comedy track. Moreover, the lack of big budget films signed by the actor and the emergence of Santhanam, saw Vivek reach a nadir in 2012, where he only had a single release. His acclaimed work during the period involved a portrayal of a don in Padikathavan (2009), an appearance in drag in Guru En Aalu (2009) and as a police officer in the Singam (2010) series. Re-emerging after a sabbatical, Vivek announced his plans to move away from his usual comedy roles after being advised by director Bala and Kamal Haasan and signed a film titled Naan Than Bala (2014), in which he played a serious role. Simultaneously he began work on another film as the lead actor in Palakkattu Madhavan (2015) opposite Sonia Agarwal, while appearing in another parallel lead role with Karunas in Sakthi Chidambaram's unreleased Machan. Since his return, Vivek has been recalled into the industry by film makers to appear again in bigger budget films and has since worked on Velraj's Velaiyilla Pattathari (2014), Gautham Menon's Yennai Arindhaal (2015), Aishwarya Dhanush's Vai Raja Vai (2015)
Vivek was born in Sankarankovil and got married to Arulselvi, with whom he has three children: Amrithanandini, Tejaswini and Prasanna Kumar, who died in 2015, aged 13, due to brain fever. Vivek graduated from The American College in Madurai Vivek was the brand ambassador of Mirinda softdrinks in 2003. As of 2011, he is the ambassador of Nathella jewellery.
Vivek launched Green Kalam, under the guidance of former President of India A. P. J. Abdul Kalam. "Green Globe Project”, a Campaign against global warming, which had attained its mission of planting billion trees for billion people all over the state.
Vivek has won the Filmfare Award for Best Comedian – Tamil for Run (2002), Saamy (2003), and Perazhagan (2004). He won the Tamil Nadu State Film Award for Best Comedian five times for Unnaruge Naan Irundhal (1999), Run (2002), Parthiban Kanavu (2003), Anniyan (2005), and Sivaji (2007). His other creative awards include International Tamil Film Award for Best Comedian, Variety Cinema Award for Best Comedian, Asianet Film Award for Best Comedian, and Edison Award for Best Comedian. He also won the Tamil Nadu State Film Honorary Award - Kalaivanar Award in 2006.