Oviya began her career as an actress by portraying supporting roles in Malayalam films, notably working in Kangaroo (2007) and Puthiya Mukham (2009) starring Prithviraj and as one of the lead characters in the college drama Apoorva (2008). Oviya then worked towards completing a BA in Functional English at Vimala College in Thrissur, before director Sargunam approached her for Kalavani (2010). Sarkunam cast her in the leading female role after seeing a picture of her online and was convinced that he had found the correct actress to portray the role despite reservations from the producer. She was featured opposite Vimal, and the film subsequently gained positive reviews and became a sleeper hit at the box office. Critics praised Oviya's performance of a village-based schoolgirl, with a critic from the Hindustan Times stating "Oviya’s marvellous expressions convey her gratitude, and she uses her eyes to say it all". Similarly, a reviewer from The Hindu stated "Oviya looks cute and emotes well, which is a rarity these days".
Following the success of Kalavani, Oviya signed several small-budget films including Jeevan's Amara, Vengai, Mugam Nee Agam Naan, Sevanu and Rasu Madhuravan's Muthukku Muthaaga (2011), but only the latter had a theatrical release. While several films were stopped due to financial reasons, Oviya had to opt out of a few films after inadvertently muddling her dates. Portraying the role of a college basketballer in Muthukku Muthaaga, Oviya worked through the pain barrier for the film after fainting on the sets following an illness. The film, however, opened to negative reviews with a critic from Behindwoods.com stating Oviya's character was "annoying". During the period, she was also seen in two further Malayalam films Puthumukhangal (2010) and Manushyamrugam (2011), despite making claims that Malayalam films were "uninteresting and boring". The Kannada remake of Kalavani titled Kirataka (2011) won Oviya more critical acclaim, with a reviewer from Rediff.com stating she "charms her way through the film", though a proposed Telugu remake later fell through. Oviya was also seen in a guest appearance in K. S. Ravikumar's romantic comedy, Manmadhan Ambu (2010), where she featured alongside Kamal Haasan and Madhavan. Post-release, the actress revealed that she appreciated the opportunity to work alongside big actors but was disappointed that several of her scenes were edited out of the film.
Over the following three years, Oviya prioritised her work in Tamil films appearing in several small and mid-budget projects and alternated between performance-based and glamorous roles. In Pandiraj's critically-acclaimed drama film Marina (2012), Oviya and her co-star debutant Sivakarthikeyan portrayed a couple who frequent Marina Beach, with a critic describing their performance as "absolutely enjoyable and hilarious". Likewise, the black comedy Moodar Koodam (2014) and the thriller Madha Yaanai Koottam (2014) also featured Oviya in performance-based roles and both won critical acclaim. She portrayed a glamorous role for the first time in Sundar C's comedy Kalakalappu (2012), where she worked alongside a star cast of Shiva, Vimal and Anjali. The film opened to positive reviews and performed well at the box office, becoming her most profitable film to date. Following further glamorous roles in unsuccessful films such as Sillunu Oru Sandhippu (2013) and Pulivaal (2014), Oviya scored another success with her role as a dainty, hot girl in Deekay's horror comedy Yaamirukka Bayamey (2014). Critics also praised her performance, with a reviewer from the Deccan Chronicle stating "as the girl-next-door-unafraid-of-her-sexuality, Oviya is perfect".
Oviya's acting career began to decline after 2014 and she was primarily offered glamorous roles in low-profile films. She was cast opposite veteran actor Sarathkumar in the unsuccessful Sandamarutham (2015) which garnered negative reviews, while her subsequent Tamil films, C. V. Kumar's heist comedy 144 (2015) and Sundar C's horror comedy Hello Naan Pei Pesuren (2016) did not perform as well as anticipated at the box office. Another project, the female-centric Bhogi co-starring Trisha and Poonam Bajwa, was also stalled despite the shoot progressing. She subsequently moved on to portray a role in the low-budget Hindi film Yeh Ishq Sarfira (2015) and then the leading role of a city girl in the Kannada film, Mr. Mommaga (2016).
In 2017, Oviya took part in the Tamil reality television show Bigg Boss hosted by Kamal Haasan for the Star Vijay channel. Oviya gained instant popularity on the show through her charm and honesty, in comparison to other housemates. While enjoying a cordial relationship with Arav, she was repeatedly targeted by other housemates including Gayathri Raghuram, Namitha, Julie and Shakthi and her clever responses and positive attitude to the bullying won over audiences. Voters repeatedly kept her in the show despite her being up for eviction at multiple instances, while she garnered a "cult following" on social media with phrases such as "Oviya Army" regularly trending. Her behaviour and positive attitude on the show also attracted other celebrities to tweet in appreciation of her, with the likes of Priya Anand, Nivetha Pethuraj, Sathish and Karunakaran amongst others praising her on social media. The popularity of Oviya reached such a high in late July 2017 that the makers of an unrelated Tamil film, Balloon (2017), included a song titled "Neenga Shut Up Pannunga" and dedicated it to the actress. Likewise, several other songwriters created their own "Oviya Anthems" and released them online.
In early August 2017, following a spat on the show with Arav, Oviya quit the show on medical grounds. Prior to her exit, she deliberately jumped into the swimming pool to force her departure, prompting the police to briefly investigate a potential suicide angle to the move. Despite widespread calls on social media for her to return to the show, Oviya released a video confirming that she had no interest in going back into the Bigg Boss House and would take an extended break and prioritise film opportunities. She also called for the public to forgive Shakthi and Julie for their behaviour towards her on the show.
Her acting career also saw positive developments following her stint on the show and her subsequent popularity. A long-delayed, small-budget film titled Seeni was renamed to Oviyaava Vitta Yaaru to cash in on the actress's new found fan following. Likewise, her Malayalam film Manushyamrugam from 2012, was dubbed into Tamil and prepared for release under the title Police Rajyam. Filmmakers including Sundar C, C. S. Amudhan and Santhosh Jayakumar announced their interest in signing the actress for roles in their film Kalakalappu 2, Thamizh Padam 2 and Iruttu Araiyil Murattu Kuthu.Television
Bigg Boss (2017)