Best remembered for her portrayal of Malar in the 2015 coming-of-age musical-romantic comedy Premam, Sai Pallavi in an Indian film actress. Apart from being an actor, Sai is also a trained dancer and has appeared on dance reality shows such as Ungalil Yaar Adutha Prabhu Deva and Dhee Ultimate Dance Show (D4). Although her first screen presence was an uncredited role in the Kangana Ranaut-starrer Malayalam romantic thriller Dhaam Dhoom in 2008, she gained recognition after Premam for which she won the Filmfare Award for Best Female Debut - South as well as the SIIMA Film Award for Best Debut (Female). Following the success of her debut, she was seen in Kali (2016), making her award-winning debut in the Malayalam film industry.

In 2017, the actress made her debut in the Telugu film industry with Sekhar Kammula`s Fida, where she was seen portraying the role of an independent village girl called Bhanumathi. Pallavi won Filmfare Award for Best Actress - Telugu for her performance in the film. Her other projects include Maari 2 (2018), Padi Padi Leche Manasu (2018), NGK (2019) and Athiran (2019), which re-released in Telugu as Anukoni Athidhi (2021). Her other notable works include Paava Kadhaigal (2020), Love Story (2021), Shyam Singha Roy (2021), Virata Parvam (2022) and Gargi (2023).