Joining the Indian Civil Service in 1923, he was appointed a Commander of the [[Order of the British Empire]] (CBE) in 1937,ref a Companion of the [[Order of the Indian Empire]] (CIE) in 1939ref and was knighted as a KCIE in 1946.ref
During his career with the ICS, Pillai was appointed to various secretarial positions in the then [[...|United Provinces]]. In 1928, he married an Englishwoman, Edith Minnie Arthurs (d. 1976); the couple had two sons.
Following his service as the first Secretary of External Affairs of an independent India, Pillai served as the Commissioner General for Economic and Commercial Affairs in Europe until 1953, residing in Paris. He received an honorary doctorate from Kerala University in 1953. He was a founding member of the first Governing Body of [http://www.ncaer.org NCAER], the [http://www.ncaer.org National Council of Applied Economic Research] in New Delhi,India’s first independent economic policy institute established in 1956. Pillai was awarded the [[Padma Vibhushan]] in 1960 and was made an honorary Fellow of , his old college, in 1970. During the 1960s, he served as managing director of two business firms in New Delhi, after which he emigrated to the United Kingdom in 1968.
In his last years, Pillai resided at 26 Hans Place in [[Kensington]], Knightsbridge. He died on 31 March 1992, just short of 94.
[[Nisha Pillai]], the former BBC presenter is his grand-daughter.ref