She began her career in Tamil film at the age of fourteen as a dancer. She debuted as an actress in director Lisa Baby's Nizhale Nee Sakshi but this film was shelved. (It was later completed with Vidhubala as heroine.) Veteran actor Vijayan rechristened her Seema during the filming of Nizhale Nee Sakshi.
At the age of 19, Seema starred as the heroine in her first movie in Malayalam titled Avalude Ravukal (Her Nights), directed by I. V. Sasi. Seema acted in a large number of movies with Jayan, one of the top actors of the time and the pair was one of the most popular in Kerala. Seema brought fashionable western dresses such as miniskrts, bell bottom pants and sleevless T-shirts into the mainstream in Malayalam Cinema, at a time where Saree and Blouse was the de facto way of dressing for herioines in Malayalam movies. She continued acting till 1988 awhen she took a break after the Malayalam movie Mahayaanam. Seema became active again in 1998 in Olympiyan Anthony Adam. Seema won the Kerala State Film Award for Best Actress in 1984 and in 1985, and is known for her versatility. Vishudha Shanthi, a biography on her life was published by Didi Damodaran, a famous writer, in 2011. She well known for her character Nachiyar in Sun TV serial Thangam. She achieved the Lifetime achievement award at the 59th Idea Filmfare festival at Chennai.
Seema was born as only child to Chennai settled Malayali parents, Madhavan Nambiar and Vasanthy, at Purasawalkam, Chennai. Her father was from Thalassery and mother was from Ambalamedu, Thrippunithura. Her father was working with T.V.S Parcel Service, Madras. He divorced her mother and left when she was 7 years old and remarried later. She grew up at Choolaimedu, Kodambakkam with her mother. She has two younger step brothers and a younger step-sister, Lakshmi. She had her primary education from P.N. Dhawan Adarsh Vidyalaya, Chennai.
She is married to famous Malayalam movie director I.V. Sasi on 28 August 1980. The couple have a daughter Anu Milan and a son Ani sasi. Anu has acted in Sasi's movie Symphony.