After a short stint with modelling, Nair made her acting debut with the 2012 Malayalam film Poppins directed by V. K. Prakash. Since then, she has appeared in a number of critically acclaimed films across all four South Indian film industries, such as Story Kathe (2013), Yennai Arindhaal (2015) and Uttama Villain (2015). Her performance as a young journalist in her first Kannada film Story Kathe won her the Best Kannada Debut Actress Award at the South Indian International Movie Awards, while her portrayal of a vengeful wife in Yennai Arindhaal won her praise from critics. In 2015, she also starred in the critically and commercially successful film Vascodigama, portraying an English lecturer.
Parvatii Nair was born in Abu Dhabi, United Arab Emirates into a Malayali family and has a elder brother named Shankar. She did her schooling at Our Own English High School in Abu Dhabi. She went on to graduate in Computer Science and Engineering from Manipal Institute of Technology in Manipal, Karnataka, India, hoping to work as a software engineer. As a school student, she won a Guinness certificate for being part of the team that made the longest painting in the world. She became a full-time model after she participated "Miss Karnataka" in 2009, and went on to be an ambassador for Mysore Sandal soap. She won "Navy Queen Kerala" in 2010, before appearing in numerous print and television commercials. As a model, she has endorsed brands like Anchor, Asian Paints, Malabar Gold, Mazaa Prestige, Reliance and Tata Diamonds. Nair had also expressed interest in participating in the Femina Miss India pageant after winning the state-level title, but could not apply as a result of the competition's height eligibility. After working as a model, she began appearing in short films, music videos and documentaries.
After working in a jewellery commercial for director V. K. Prakash, Nair was offered a role in his feature film Beautiful (2011), but refused the opportunity down as she was unsure whether to pursue a career in films. She later accepted to feature and make her acting début through Prakash's anthology film Poppins (2012), and worked on the project alongside her commitments in other Malayalam films. She played further roles as a traditional bride in the horror film Yakshi – Faithfully Yours (2012) and in Shalil Kallur's drama film. She subsequently began working on bigger budget films in the Malayalam film industry and signed on to portray Jayasurya's wife in the action anthology D Company (2013), as a part of the segment Gangs of Vadakkumnathan, which won positive reviews. Nair made her debut in the Kannada film industry through Story Kathe (2013) which earned her recognition as the Best Debut Actress in Kannada films at the 3rd South Indian International Movie Awards. Portraying a television journalist in the film, who tries to win patent rights for a medical student, her role was appreciated by critics and the film performed well at the box office. Moreover, in 2013, besides from films, Nair worked as a judge in the first modelling based Malayalam reality show Super Models on Amrita Television. She also appeared in a music video, "Ariyathe Ninayathe" by Vineeth Sreenivasan and was included in Bangalore Times' "Most Desirable Women of 2013" list. She was also included in the most desirable women 2015,2016,2017 lists from Kochi as well . She gave motivational talks at TEDx Bangalore and was invited to speak at Rotary Club and various other avenues .
After playing a supporting role in Saji Surendran's Angry Babies in Love (2014), Nair moved on to work on two big-budget Tamil films during the course of 2014 and shot for Gautham Menon's Yennai Arindhaal (2015) and Kamal Haasan's Uttama Villain (2015). Nair was cast alongside Ajith Kumar, Trisha and Anushka Shetty in Yennai Arindhaal after a successful screen test, for which she had to appear without make-up. Talking about opportunity, the actress stated it was "a dream-come-true" and to be cast in the project was "huge encouragement", and made reference to Menon's dignified portrayals of female characters. Portraying Elizabeth, the vengeful wife of Arun Vijay's character, the film and her performance won critical acclaim with a reviewer from Silverscreen.com stating she displays "awesome ruthlessness" and that she "nails the part". Nair also successfully auditioned for a role in Uttama Villain, directed by Ramesh Aravind, and portrayed the girlfriend of Kamal Haasan's son. Featuring alongside an ensemble cast, her role was extended as the shoot progressed and Nair revealed her delight at working with Kamal Haasan, stating it was like "going to an acting school". The film opened to positive reviews and marked the actress's most high-profile project till date. She then appeared in the Kannada film, Vascodigama (2015), where she portrayed a college lecturer alongside Kishore. Nair also made her debut as a singer through the film, for a song which featured Kannada and English lyrics. The film opened to positive reviews from critics and performed well at the box office. Nair's portrayal won acclaim, with a critic from Indiaglitz.com noting that she "suits the role precisely" and another reviewer stating she was "utilised well" in the film.
She will be seen in two of Eros International's forthcoming Tamil projects, the period film Enkitta Modhadhe and the romance film Pirai Thaediya Naatkal opposite Ashok Selvan. She has furthermore signed James and Alice alongside Prithviraj, the Telugu film Shobhan Babu and a road thriller in Malayalam to be directed by John J. Philips. She is also committed to the Tamil film Koditta Idangalai Nirappuga directed by R. Parthiepan, and the Malayalam film Tham Thakam Pathakam.
Nair received the Indian Affairs "Most Promising Actress 2017" award at the Satya Brahma founded 8th Annual India Leadership Conclave in Mumbai on 4 August 2017.
Nair has been a regular guest model at Indian fashion weeks, often appearing in the main display of shows. At the 2013 Chennai International Fashion Week, Nair was the main model for Sakshi Bindra's clothing line, Sakk, and was the first day's "showstopper". She wore costumes styled by Vivek Karunakaran as a part of the Walk of Pride charity event held at the Park, Chennai in April 2015. During August 2015, she attended the India Luxury Style Week and Chennai's Fashion Couture Week within a fortnight, to promote the fashion industry in the city. In 2016, she took part in the first day of the Bangalore Fashion Week, wearing traditional wear by designer Mable Thomas, and then at the Keralan Fashion League. Her experience as a successful model saw her work as a main judge on Amrita TV's reality show, Supermodels during 2013. She also worked alongside four other actresses as the judge of the beauty pageant, Miss India Bangalore 2015 during December 2015. Her popularity as a model had initially helped her make a breakthrough into the film industry, and saw her get recognition across all four South Indian states.
Nair was announced as the brand ambassador of the Karnataka Bulldozers team during the 2016 Celebrity Cricket League and attended the team's fixtures across South India as a part of her role. She shared ambassadorial duties with actress Sharmiela Mandre and revealed that she had grown up following the sport during her childhood in the United Arab Emirates, where her father and brother had played regularly. The actress also attended matches played by Royal Challengers Bangalore during the IPL Season of 2015 and played cricket as a part of the shoot during her film, Uttama Villain (2015). In 2016, she was announced as one of the ambassadors of the Nellai Dragons team led by Jayam Ravi at the Nadigar Sangam's Star Cricket competition. Nair has also been a part of charity events including the Clean Bengaluru Challenge in November 2014 initiated by Times Foundation, where she helped sweep the streets of Vasanthnagar in the city.