In 1967 Doy ran for the Senate where he hoped to continue his crusade for justice for the poor. He emerged victorious as the youngest Nacionalista elected senator. Thus began a distinguished public service career that spanned nearly 37 years.
On his first year as Senator he was Chairman of the Senate Committee on Justice, Committee on Economic Affairs, Committee on Government Reorganization, and Committee on Community Development.
Senator Salvador H. Laurel authored five “Justice for the Poor Law” known as the “Laurel Laws”, nine laws on Judicial Reforms (1968-1970); Government Reorganization Act (1967-1970) and Amendments to the Land Reform Code (1971). He also wrote a book on penal reforms and another on Land Reform entitled “This Land Is Mine”. He was consistently voted “Most Outstanding Senator of the Year” 1968, 1969, 1970 and 1971.
In 1972 Doy was the first Philippine government official to visit Mainland China then under Chairman Mao Tse Tung. He was met by Premier Zhou En Lai and Vice Premier Li Xinnian and other high officials of the Chinese government. Upon his return, he submitted an extensive report to the Senate on his China visit. He strongly advocated for the resumption of friendly ties with the PROC and the adoption of a one-China policy (which eventually became the official stand of the Philippines).