Santhoshi was born to Gopala Krishna Moorthy and television actress Poornima. She first appeared in a television series, when she was eight years old, acting alongside her mother. She then debuted in the Tamil film Baba, starring Rajinikanth, playing the sister of Manisha Koirala. Subsequently, she played supporting roles in several Tamil films as Aasai Aasaiyai, Bala, Maaran and Military, before enacting lead female roles and foraying into other South Indian film industries as well. She played the second female lead in Samuthirakani's Unnai Charanadaindhen (2003) and also played a starring role in Kadhal Samrajyam directed by National Film Award-winning director Agathiyan; the latter, however, remains unreleased. She made her debut in the Telugu film industry with the film Jai (2004) opposite Navdeep and debuted in Kannada in 2006 with the film Honeymoon Express. She also appeared in popular Telugu films such as Nuvvostanante Nenoddantana and Bangaram, enacting supporting roles. Her performance in the former fetched her the Nandi Award for Best Female Comedian. Since 2007, she appeared in the popular series Arasi. She was crowned "Miss Chinnathirai 2007" at a beauty contest organized for television actresses.