Rashmika began modelling in 2014. She won the Clean & Clear Fresh Face of India title the same year and was made the brand ambassador of Clean & Clear. Then she got the title of TVC in Lamode Bangalore's top model hunt 2015. Her pictures from the competition impressed the makers of the film Kirik Party who then cast her as the female lead for the film in early 2016. In an interview with The Times of India, she recalled: "The makers of Kirik Party saw a picture of mine from the Clean & Clear Fresh Face of India 2014 competition — one in which I was dancing during the college round — and approached me to act in the film. So, it really got things going. I always wanted to be in films." She was cast as Saanvi Joseph, a college-goer, and the love interest of Karna (played by Rakshit Shetty). The film opened to widespread acclaim from critics and audiences alike. Alongside, Rashmika's performance received praise and won SIIMA Award for the Best Actress (debut) 2016. Sunayana Suresh of The Times of India wrote, "Rashmika Mandanna as Saanvi is easily that pin-up girl in college and she breathes her path." The film's reviewer for The New Indian Express wrote, "Rashmika Mandanna has outshone in the film along with the main character".
Rashmika met actor Rakshit Shetty for the first time at the sets of Kirik Party in 2016. They began dating after having worked together; they got engaged in July 2017 in a private ceremony in her hometown Virajpet.
As of March 2017, Rashmika is filming with Harsha's Anjani Putra opposite Puneeth Rajkumar. She has also signed Chamak opposite Ganesh. She made her Telugu film debut opposite Naga Shourya with the film titled Chalo.