Kennedy grew up in Orange City, Iowa, a Reformed village with a large portion of the population having roots in Netherlands. His mother is a Dutch-born immigrant.
He studied foreign service at Georgetown University, obtaining his B.S. in 1986, Christian studies at Calvin Theological Seminary in Grand Rapids, Michigan, obtaining his M.A. in 1988, and took his PhD in history from the University of Iowa in 1995.
He performed several jobs in the field of history before becoming an assistant professor of European history and research fellow at the A. C. Van Raalte Institute, Hope College in Holland, Michigan in 1997.
In 2003, Kennedy moved to the Netherlands because he was appointed a professor of modern history (20th century) at the Vrije Universiteit Amsterdam. In 2007 he changed to the University of Amsterdam, where he became a professor of the history of the Netherlands. In 2009 he succeeded professor Piet de Rooy, head of the section of the history of the Netherlands. Between 1 October 2015 and December 2020, Kennedy was Dean of University College Utrecht.
Kennedy takes a special interest in post-war Dutch history. Because of his Christian belief he considers himself a Christian historian although he is reserved to point out how God is guiding human history.
Politically, he characterizes himself as an independent. However, in the presidential campaign of 2004 he was in favor of John Kerry, the presidential candidate of the Democrats.
James Kennedy is married to Simone Kennedy-Doornbos, a Dutch politician for the ChristianUnion, who has been serving as a Senator since 2023. They have three children. The Kennedy family is a member of the Reformed Churches in the Netherlands (Liberated), an orthodox reformed denomination.
