James Mickens has broad interests in systems design and security. Much of his research focuses on the problems that arise when distributed systems must scale to many users and many machines. Mickens investigates how to provide high performance to those systems despite the presence of faulty or subverted machines. He also studies mechanisms for protecting user data from other users and the system itself (which may not be fully trusted by users).

On the client-side, a primary focus of his research is on the architecture of web applications—this architecture includes both JavaScript programs and the web browsers which run those programs. For example, how should a browser compose untrusted content from multiple origins in a way that still permits safe cross-origin communication? What kinds of tools can we build to allow developers to debug the complex, nondeterministic program faults that users encounter? On the server-side, Mickens studies fast, reliable datacenter storage, as well as security frameworks that allow users to restrict the ways that datacenters can manipulate sensitive user data. 

Mickens received a B.S. degree in Computer Science from the Georgia Institute of Technology in 2001. In 2008, he received a Ph.D. in Computer Science and Engineering from the University of Michigan. After graduate school, Mickens went to Microsoft Research in Redmond, WA, where he spent six years as a member of the Distributed Systems group. During the Fall 2014 semester, he was a Visiting Professor at MIT, working with the Parallel and Distributed Operating Systems group. In Fall 2015, he became an Associate Professor at Harvard and was awarded tenure in 2019.