Pillai was appointed a lecturer at the University of Kerala in 1945 and worked there for six years until he went to the United States in 1951. After studying for one year at Princeton, Pillai went to the University of North Carolina where he was awarded a doctorate in statistics in 1954.
His first post was as a statistician with the United Nations, a post he held from 1954 until 1962. Part of his duties in this post involved him founding the Statistical Center of the University of the Philippines. He was a visiting Professor and Advisor to the University over a number of years and supervised graduate students there.
In 1962 Pillai was appointed Professor of Statistics and Mathematics at Purdue University. In  his contributions to Purdue as described as follows:-
In the 23 years he served Purdue, he directed the research of 15 Ph.D. students. He was also an active consultant on several projects both within and outside the University. He was a close friend of his students and maintained a correspondence with most of them, some of whom are in remote parts of the world.Pillai's research was in statistics, in particular in multivariate statistical analysis. In  his work is described:-
... he obtained the probability distributions of statistics relating to several multivariate procedures. Perhaps his best known contribution is the widely used multivariate analysis of variance test which bears his name.Pillai was honoured by being elected a Fellow of the American Statistical Association and a Fellow of the Institute of Mathematical Statistics. He was an elected member of the International Statistics Institute.
As well as his work at Purdue in developing the graduate programmes these Pillai was a keen golfer. This is described in :-
His unique and unforgettable style charmed his playing companions and confused his opponents in the Purdue Staff League. His performances in the League matches were legendary.
Article by: J J O'Connor and E F Robertson