 He was appointed Professor of Mathematics and Head, Department of Mathematics in 1974 and Dean of the Faculty of Science in 1975.Samaranayake was the founder of the Department of Statistics and Computer Science (DSCS) in 1985 and of the Institute of Computer Technology (ICT) of the University of Colombo in 1987.These two institutions were merged as the University of Colombo School of Computing in 2002.