José A. Cuesta graduated in Physics at Universidad Complutense de Madrid in 1987 and obtained his PhD in Physics at the same university in 1992. That year, he joined the Department of Mathematics of Universidad Carlos III de Madrid, where he became Associate Professor in 1995 and Full Professor in 2011. He has been a member of the Institute for Biocomputation and Physics of Complex Systems (BIFI) since March 2012; an associate researcher at the York Centre for Complex Systems Analysis (YCCSA), University of York, since September 2013; and a member of the UC3M-BS Institute of Financial Big Data (IFiBiD) since September 2015. His Erdős number is 3.

For a long period — including his PhD — he applied density functional theory to the study of phases and phase transitions in complex fluids, such as liquid crystals, mixtures and colloids. When he moved to Universidad Carlos III de Madrid, he worked for a short period on semiconductor theory. His current research interests lie in the theory of complex systems, both biologically and socially motivated, with special emphasis on evolutionary dynamics and microbial ecology.