[5] In 2004, Leskovec received a Diploma in Computer Science from the University of Ljubljana, Slovenia, researching semantic networks-based creation of abstracts, using machine learning; in 2008 he received a PhD in Computational and Statistical Learning from the Carnegie Mellon University.

[citation needed] After finishing his PhD, Leskovec worked as a postdoctoral fellow at Cornell University for a year.

His general research area is applied machine learning and data science for large interconnected systems.

His research finds applications in a variety of settings including commonsense reasoning, recommender systems, computational social science, and computational biology with an emphasis on drug discovery.

[6] Leskovec co-founded a startup called Kosei in 2014 that was acquired by Pinterest in 2015.