Born in Ayyampalayam near Pollachi, in Coimbatore district of Tamil Nadu, Viswanathan is a third-generation police officer in his family.

In the 1990 UPSC results, he secured the first rank from the state of Tamil Nadu and opted for the Indian Police Service.

After the 14 February 1998 serial bomb blasts in Coimbatore City that resulted in the death of 69 people, Viswanathan was chosen to be posted as the Superintendent of Police, State Special Branch.

During 2002 he also held full additional charge of the Cochin Anti Corruption branch of CBI, looking after the Kerala state.

During this time the activities of Muslim fundamentalists along with the prosecution of the accused Coimbatore serial bomb blast cases created quite a tension in the state and he played an important role in providing intelligence inputs to handle the situation On promotion as the Inspector General of police, he was posted as the Joint Director in the Directorate of Vigilance and Anti-Corruption.

Within three months of taking the post, there was a police action against lawyers in the Madras High Court campus on February 19, 2009.

This was to enable him to take over as the officer on special duty (OSD) to the newly appointed Union Cabinet Minister of Chemicals and Fertilizers M.K.Azhagiri.

From TN House he was transferred as the Chief of Vigilance and Security in Tamil Nadu Newsprint and Papers Limited.

On promotion as the Additional Director General of Police (ADGP) in November 2015, he was posted as the Chief Vigilance Officer of the Metro Transport Corporation.

[17][18] Tamil Nadu also was adjudged as the best state for the maintenance of law and order, by India Today in 2018 for which the contribution of Greater Chennai Police was substantial.

[19][20][21][22][23] A white marble bust of Colonel John Pennycuick,[24] the British Army engineer who sold his property in England to build the Mullaperiyar dam, was gifted to his descendants by Dr Viswanathan.

This statue was unveiled at St Peter's Church in Frimley, UK on 12 January 2019 by Indian High Commission Minister A S Rajan.

Nitin Jairam Gadkari, Hon’ble Minister for Road Transport & Highways, Shipping and Water Resources, River Development & Ganga Rejuvenation, Government of India, at New Delhi.

[27][28] The SKOCH awards [29] are conferred by an independent organisation recognising projects and institutions which undertake efforts in the areas of digital, financial and social inclusions for the betterment of the country and seek to celebrate human excellence and agents of change in the Indian society.

The Chennai City Police won three awards in 2019 in recognition of their efforts in the areas of digital, financial and social inclusions for betterment of the country.