Piaa Bajpai was born in Etawah but resettled in Delhi at 18 to attend a computer course while hoping to gain a break in films. Though her parents opposed her decision, she enrolled for a diploma in computer science, whilst undertaking small jobs such as working as a receptionist and tutoring in order to earn money to make a good portfolio. However after a year, the office job left her restless and she relocated to Mumbai on her own money. Piaa then began to work as a dubbing artiste for serials, but found the job depressing and moved onto modelling appearing in print-ads, commercials and music videos. Most notably, she went on to feature in adverts for Cadbury alongside veteran actor, Amitabh Bachchan and Sonata with cricketer, Mahendra Singh Dhoni. She was eventually signed on by noted film-maker Priyadarshan to appear in a commercial he directed and it became a platform for her to break into films.
After appearing in Priyadarshan's commercial, he offered her a chance to play a part in his Tamil film production, and Piaa accepted the offer after an audition. The comedy film, Poi Solla Porom, was directed by A. L. Vijay and featured Karthik Kumar and Nassar in pivotal roles. Upon release the film won critical acclaim and favorable reviews, with Piaa's performance labelled as "bubbly and cheery". She went on to feature in Raju Sundaram's Aegan as a college student, with the film featuring her alongside Ajith Kumar, Nayantara and Navdeep. The film, a remake of 2004 Hindi film Main Hoon Na, received average reviews whilst Piaa's portrayal of Amrita Rao's character from the original also garnered a mixed response with a critic citing "she hams it", whilst another cited "she was promising" in her role. In 2009, she appeared in a low-budget Telugu film, Ninnu Kalisaka and won positive acclaim for her portrayal of her character.
On the final day of sets for Aegan, Ajith Kumar introduced her to director Venkat Prabhu, who signed her for Goa sixth months later, to appear as the love interest of Jai in the film. During the making of the film in Langkawi, the crew cited that the hotel was haunted and Piaa came out with an account of an eerie experience in her hotel room. Goa became her big break and Piaa won critical acclaim for her portrayal of Goan girl Roshini with critics citing that she looked "promising" and "endearing", while the award-winning song "Idhu Varai" was shot featuring her character. With the help of director Vijay, she was selected to portray the lead role in Siddharth Chandrasekhar's comedy Bale Pandiya alongside Vishnu, becoming her first major release as a lead heroine.
Piaa's next release was K. V. Anand's political thriller Ko, in which she portrayed Saraswathi, a journalist, alongside Jeeva, Karthika Nair and Ajmal. Prior to release Piaa has revealed that the film will be a milestone in her career, citing that she is waiting for the release of the film adamantly. The film went on to win commercial and critical acclaim, with Piaa's performance winning particular praise. She appeared in her first Malayalam language film, Masters opposite Prithviraj.