Smitha started as a touch-up Artist for an Actress and soon got a break in small character roles. Later she was discovered by Vinu Chakravarthy, Director at a flour mill near AVM studios. He changed her name to Smitha and took her under his wing; his wife taught her English and arranged for her to learn dancing, though soon, due to her marked sex appeal, she switched to roles of cabaret Dancers and vamps and inevitably found herself typecast. After garnering much notice and acclaim with her first major role in the Tamil film Vandichakkaram, in 1979, Smitha assumed the screen name "Silk", after her character's name in the movie. After it became a big hit, she could not escape typecasting, severely limiting her range throughout her career.

Smitha went on to star in Telugu, Tamil, Malayalam, Kannada and a few Hindi films. Her dance numbers and bold performances in films like Moondru Mugam made her the ultimate symbol of sensuality in South Indian cinema. Her item numbers in films like Amaran, Hallimeshtru Kannada were also celebrated at the box office. Some film critics, historians and journalists have referred to her as a "soft porn" Actress. A vast majority of her movies are considered 'softcore' by Indian standards and a Common theme is her playing a freakishly strong agent in skimpy bikinis beating up huge thugs. Her acting prowess did not go completely unnoticed, and in her rare non-sexual roles she impressed critics and audiences, such as her portrayal of a wife hurt by her role in her husband's rape of their maid (which she passively allowed by not preventing him from entering the maid's bathroom and standing "guard" during the shameful act, to prevent embarrassment to their family) and when she poignantly admitted her mistake in her confrontation of her husband in Alaigal Oivathillai (1981). One of her films, Layanam (1989), has earned a cult status in the Indian adult film industry and was dubbed in numerous languages, including Hindi (Reshma Ki Jawani, 2002), which, too, acquired cult status. Her most respected film is Moondram Pirai by Balu Mahendra, remade in Hindi as Sadma, with much of the top-drawer cast, including Sridevi, Kamal Hassan, and Silk Smitha reprising their roles.

In the morning of September 23, 1996, Smitha was found dead in her Chennai home, much to the shock of her fans. The reason behind her death remains a mystery. Some believe it was suicide, due to depression over her debt accumulated from producing movies, while others call it foul play. A few months later it was declared in the postmortem report that Smitha died of alcoholism and alcohol intoxication.

In 2011, a biographical film on Silk Smitha's life, titled The Dirty Picture, was produced in Hindi by Ekta Kapoor. The movie was directed by Milan Luthria and starred Vidya Balan (who later won National Film Award for Best Actress). The movie was released on Smitha's birthday (2 December 2011) and received favourable reviews. Reports suggest that the family of Silk Smitha, on whom the film is based, is not happy with the movie. Smitha's brother V Naga Vara Prasad claimed the film was made without the family's consent. After the claim, Ekta Kapoor immediately changed her statement by quoting The Dirty Picture is not based on Silk Smitha's life.

A Malayalam film titled Climax starring Sana Khan as Silk Smitha released on 24 May 2013.