Born on April 5, 1996, in Virajpet, a town in the Kodagu district of Karnataka, Rashmika Mandanna comes from a Kodava Hindu family. Her parents are Madan and Suman Mandanna. Her father owns a coffee estate and a function hall in her hometown. As a child, her family faced financial difficulties, which she says has influenced her relationship with money. She attended Coorg Public School, a boarding school in Gonikoppal. She has a younger sister. She later attended M.S. Ramaiah College of Arts, Science, and Commerce in Bengaluru, where she earned a bachelor's degree in Psychology, Journalism, and English Literature.

Rashmika's career began with modeling after she won the Clean & Clear Fresh Face of India contest in 2014. Despite initially declining acting offers, a college professor convinced her to audition. She made her acting debut in the 2016 Kannada romantic comedy, Kirik Party, which became one of the highest-grossing films of the year and earned her the SIIMA Award for Best Debut Actress. She gained further commercial success with the films Anjani Putra and Chamak in 2017.

Her breakthrough came with her Telugu cinema debut in the 2018 romantic comedy Geetha Govindam, which earned her the Filmfare Critics Award for Best Actress – Telugu. She gained wider recognition with the pan-India success of the Telugu action film Pushpa: The Rise (2021) and the historical action film Chhaava (2025). Her highest-grossing films include Animal (2023) and Pushpa 2: The Rule (2024).

In January 2025, Rashmika confirmed in an interview with The Hollywood Reporter that she is in a relationship, referring to herself as a "partner," but did not reveal the name of her partner.

Rashmika has received numerous awards, including four SIIMA Awards and a Filmfare Award South. In 2024, she was featured in Forbes India's "30 Under 30" list and was named among South India's highest-paid actresses by the Indian edition of GQ. She has also been a brand ambassador for various products and was named the first Indian ambassador for the Japanese fashion brand Onitsuka Tiger.