 After the war, he retired from the Army and joined the Union Government and worked in various capacities such as an adviser on Tuberculosis (1946–48) and as the Deputy Director General of Health Services (1948–57).He was also associated with the University of Delhi during this period, as the head of the Department of Medicine and as the Dean of the Faculty of Medical Sciences.During his tenure with the Government of India, Viswanathan was appointed as the director of Vallabhbhai Patel Chest Institute (VPCI) when the institution was established in 1953.