Hazens wife, Margee (née Margaret Joan Hindle), is a science writer and published historian. Her late father, Howard Brooke Hindle, PhD (1918–2001), was a historian who studied the role of material culture in the history of the United States and served as Director of the National Museum of American History from 1974 to 1978.  Hazens late brother, Dan Chapin Hazen, PhD (1947–2015), was an academic research librarian who had been affiliated with the libraries at Harvard, and was particularly recognized for his accomplishments to the Center for Research Libraries and advocacy of collections from Latin America.  Harvard has memorialized Dan Hazen by establishing two chairs in his name.
The Hazens have two children: Benjamin Hindle Hazen (born 1976) and Elizabeth Brooke Hazen (born 1978).