Palfrey began his teaching career as teaching fellow at Harvard University, where he taught internet law courses from 2000-2001. He returned to teaching at Harvard Law School in 2002 after spending a year with the Boston law firm Ropes & Gray LLP. During the 2007-2008 academic year, he was a visiting professor of Information Law and Policy at the University of St. Gallen in Switzerland. He also served as a special assistant at the U.S. Environmental Protection Agency during the Clinton administration.
Palfrey is married to Catherine Carter, and they are the parents of two children, Jack, 9, and Emeline, 6.