Viswanath began his career as a technician in a studio at Chennai and later assisted Mr. Adurthi Subba Rao in direction. He also worked as an assistant to director Ramnoth. He also wished to work as an assistant to K. Balachander and Bapu. He debuted as a director with Aatma Gowravam, which starred Akkineni Nageswara Rao. However, his full prowess in film-making flowered with a subsequent film called Siri Siri Muvva.
His films used to tackle the relevance and influence of Indian music/culture/art in the modern era. Films in this mould include Sankarabharanam ('Lord Shankara (shiva)'s Ornament'). He made a series of such classical oriented movies all showcasing the bliss in Indian art forms. The list includes Saagara Sangamam ('The place where river merges into Sea/Ocean. As per Hindu beliefs, this is supposed to be a sacred place'), Sruthi Layalu, Sirivennela ('Golden Moonlight'), Swarnakamalam ('Golden Lotus'), and Swathi Kiranam ('A Ray of Talent').
Vishwanath also made significant contributions on the social front with films like Saptapadi ('The seven Steps', signifying the sanctity of the Hindu marriage system), Swathi Muthyam ('Pure Pearl'), Swayam Krushi ("Attitude Towards Work" � conveying the message that dilligence and dedication is indispensable in achieving success), Subhodayam ('Good Morning'), Subhalekha ('Wedding Invitation' � a critique of the dowry system), Aapadhbhaandhavudu ('Savior'), and Subha Sankalpam ('Good Will').
Swathi Muthyam was India's official entry to the Oscars in 1986. Viswanath was awarded the Padma Shri by the Government of India for his contributions to Indian film.
His films mirror the erosion of cherished values of Indian culture yet he remains critical of those morals that make one stand against his fellow human. For example, in his movie Saptapadi, Vishwanath brilliantly addresses certain loopholes in an inadmissible cultural system like intercaste marriage. A temple chief-priest gets his daughter’s daughter married to his son’s son – unaware that she is musically fused to a flutist who is a Dalit (one of a lower caste, but of a higher humanness.) Later, as the priest sees the marriage falling apart, he comes to know the girl’s erstwhile bonding. It takes the priest intense introspection to realize how nasty it is to look down upon a fellow human because of caste. He could now anchor his judgment in the “content of character� rather than caste. Across numerous other films, Vishwanath has re-echoed similar social concerns that still resonate in the audiences’ minds.
The music for his films was composed by K. V. Mahadevan and Ilaiyaraaja. Viswanath has also worked with artists like Hariprasad Chaurasia, Kelucharan Mohapatra and Sharon Lowen for some of his films.
Viswanath also ventured into mainstream acting in Telugu movies such as Pandurangadu(stg*Balakrishna,Sneha, Tagore(Stg*Chiranjeevi), Aadavari Maatalaku Ardhaale Verule(stg*Venkatesh,Trisha Krishnan)and Tamil films like Kuruthi Punal(stg*Kamal Haasan,Arjun), Kakkai Chiraginile(stg*Parthiban), Mugavari(stg*Ajith), Bhagavathy(stg*Vijay), Pudiya Geethai(stg*Vijay) and Yaradi Nee Mohini(stg*Dhanush).
He is currently playing the lead in SIVA NARAYANA TEERTHAM in TTD's Sri Venkateswara Bhakthi Channel(SVBC).

Filmography
Aatma Gouravam (1965)
Private Master (1967)
Sudigundalu (1967)
Kalisochchina Adrushtam (1968)
Undamma Bottu Pedata (1968)
Nindu Hridayalu (1969)
Sabhash Satyam (1969)
Chelleli Kapuram (1971)
Nindu Dampatulu (1971)
Chinnanaati Snehithulu (1971)
Kalam Marindi (1972)
Neramu Siksha (1973)
Sharada (1973)
O Seeta Katha (1974)
Amma Manasu (1974)
Chinna Nati Kalalu (1975)
Jeevana Jyoti (1975)
Prema Bhandam (1976)
Mangalyaniki Maromudi (1976)
Jeevita Nouka (1977)
Chilanka (1977)
Kaalanthakulu (1978)
Siri Siri Muvva (1978)
Seetamalakshmi (1978)
Sankarabharanam (1979)
Sargam (1979)
President Peramma (1979)
Alludu Pattina Bharatam (1980)
Saptapadi (1980)
Subhodayam (1980)
Subhalekha (1982)
Kaamchor (1982)
Shubh Kaamna (1983)
Saagara Sangamam (1983)
Janani Janmabhoomi (1984)
Jag Utha Insan (1985)
Swathi Muthyam (1985)
Sura Sangam (1985)
Sanjog (1985)
Siri vennela (1986)
Srutilayalu (1987)
Swayamkrushi (1987)
Swarna Kamalam (1988)
Sangeeta Sangamam (1988)
Eshwar (1989)
Suthradharulu (1990)
Aapathbandhavudu (1992)
Sangeet (1992)
Swathi Kiranam (1992)
Dhanwaan (1993)
Subha Sankalpam (1995)
Chinnabbayi (1997)
Swarabhishekam (2004)
Sumaduram(2010)- starring Allari Naresh and Manjari.

Awards
National Film Awards
1980-National Film Award for Best Popular Film Providing Wholesome Entertainment -Sankarabharanam
1982-Nargis Dutt Award for Best Feature Film on National Integration-Saptapadi
1984-National Film Award for Best Feature Film in Telugu-Sagara Sangamam
1986-National Film Award for Best Feature Film in Telugu-Swathi Muthyam
1988-National Film Award for Best Feature Film in Telugu-Sruthi Layalu
2004-National Film Award for Best Feature Film in Telugu-Swarabhishekam
Raghupathi Venkaiah Award-1992
Padmashri Award.