She was born as the youngest of five children on 23 May 1989 at Kannur, Kerala to a local fisherman worker and a housewife. She did her schooling at Ursuline Senior Secondary School, Kannur and at St. Teresa’s Anglo Indian Higher Secondary School, Kannur. She completed her Bachelor of Arts in English by correspondence. She resides in Kochi, Kerala. She is a dancer in stage shows. She mentioned in an interview with John Brittas that her godfather in Malayalam movies at early stages of her career was Mohanlal.
In the mid 2010s, Poorna appeared in a series of films where she portrayed a ghost, with The Hindu labelling her as “the ghost queen of Telugu films”. She won critical acclaim for her roles in Avunu (2012) and the sequel Avunu 2 (2015), which led to film makers wanting to cast her in horror films. She turned down several similar scripts, before winning further acclaim for her role as a ghost in Raju Gari Gadhi (2015), which became a surprise hit at the box office. She tonsured her head for her role in the movie Kodiveeran (2017) but the movie did not receive a good response from the audience.
In June 2020, police arrested members of a gang on a complaint lodged by Shamna Kasim’s mother that they blackmailed her daughter. Police revealed that the gang locked film actresses in hotels rooms and forced them to accompany as escorts for transporting black money.
She is known for her work in the South Indian film industry. She started her career as a classical dancer and came into the entertainment industry following her participation in the reality-based dance competition Super Dancer on Amrita TV. She made her acting debut in the 2004 Malayalam film Manju Poloru Penkutty. Her debut Telugu movie came with Sri Mahalakshmi, while playing the lead female character in her first Tamil film, Muniyandi Vilangial Moonramandu.