He is well-known for his work on the Ptolemy and Boa programming languages, which have significantly impacted how crosscutting concerns are modularly reasoned about and how the barriers to data-driven software engineering are reduced.

He then moved to North America for his graduate studies, earning both his MS in 2004 and his Ph.D. in 2005 in Computer Science from the University of Virginia.

"[3] [4] Following his PhD, Rajan joined the Department of Computer Science faculty at Iowa State University as an assistant professor in 2005.

[10] During the COVID-19 pandemic, Rajan co-developed a data science infrastructure to improve research efficiencies for scientists who study the novel coronavirus.

[11] He helped develop and establish the National Science Foundation Dependable Data-Driven Discovery Institute at Iowa State University.