Viswanathan appeared as the cinematographer for many films since the 1970s predominantly worked in films directed by Rama Narayanan and also helped recommend actor Sathyaraj for his first role in Sattam En Kaiyil (1978).
[3] At the insistence of Kamal Haasan, he directed Sankarlal (1981) when the film's director T. N. Balu died during the shoot.
In the early 2000s, he worked on several devotional films as a cinematographer and developed his knowledge of CGI and VFX related scenes.
[5] Viswanathan went on to direct Jaganmohini (2009), a remake of the 1978 film of the same name, with Namitha and Nila starring.
Despite creating attention prior to release, it opened to mixed reviews, with a critic citing that the film felt "dated".