Professor Deltas completed his undergraduate and doctoral degrees in Economics from MIT and Yale, respectively. His dissertation focused in theoretical and empirical aspects of auctions. He joined the University of Illinois in Urbana-Champaign in 1995, and he has remained on the faculty since. In addition to that appoint, Professor Deltas spent a year at the Federal Trade Commission in Washington DC (2001-2002) and a year at the Kellogg School of Management at Northwestern University (2005-2006). He also held the appointment as Distinguished Visiting Professor of Economics at Lancaster University, UK (2016-2018). Since 2022 he has served as a consultant at EconOne.

The research of Professor Deltas spans empirical and theoretical topics in auctions, industrial organization, applied econometrics, environmental economics, and political economy. He has a special interest in competition, and has produced research on this topic in procurement, gasoline, shipping, and airlines, and also on theoretical models that apply more generally. His research has received funding from the US National Science Foundation, the US Environmental Protection Center, the US Office of Naval Research, the European Bank of Reconstruction and Development, among others.

In addition to scholarly output, Professor Deltas has had extensive administrative experience, serving in administrative capacity continuously since 2007 as Director of Graduate Studies, Associate Head of the Department, and Head of the Department.