Shamili hails from Kerala from an acting family, being the younger sister of actor Richard Rishi and actress Shalini who is married to actor Ajith Kumar. The family is a Protestant Christian. She is doing a course in Singapore and holds a degree in ‘Visual Communication’ from Women’s Christian College.
Shamili started acting at the age of two. In 1990, she acted in Bharathan’s Malootty, a film based on Jessica McClure. Her performance won her critical appreciation and the Kerala State Film Award for Best Child Artist. Her breakthrough in Tamil came with Mani Ratnam’s ‘Anjali’, in which she portrayed a mentally challenged child, which earned her the National Film Award for Best Child Artist. She also acted as a teenager in Fazil’s Harikrishnans as Mammooty and Mohanlal’s sibling. In Kannada, she acted in Dakshayini, Kadambari (1993), Karulina Kudi (1995), Bhairavi (1991) and Chinna Nee Naguthiru (1993).She worked as a model in the Milka-B Biscuit. She played her first female lead role in Anand Ranga’s directorial debut Oy! alongside Siddarth.