Michael N. Castle, whose distinguished record of service to Delaware and the nation included two terms as governor of the state and the distinction of being the longest serving U.S. representative in the state’s history, died Aug. 14, 2025, after a long illness. He was 86.

Castle served as the First State's 69th governor from 1985-1992 and represented Delaware in the U.S. Congress from 1993 to 2011. He was lieutenant governor of Delaware from 1981 to 1985 and a member of the Delaware General Assembly, serving in both the State House of Representatives and in the State Senate from 1966 to 1976. He also served as deputy attorney general.

A frequent visitor to the UD campus, Castle once said, “I have made many, many visits to this campus, including any time there is a good football game, as well as for academic and public relations reasons and to help make sure that this great University is recognized for the excellence which it has.” As governor of the state, he was an ex officio member of the University’s Board of Trustees for eight years.

In 2011, Castle officially donated his Congressional papers to the University of Delaware Library. These Congressional materials, now housed in Special Collections, include papers and records in multiple formats, including written, recorded, electronic, media and web pages.

At an informal ceremony on campus to mark the donation, he noted that during his tenure as governor and in the U.S. House of Representatives, he was well served by staff members, of whom more than two-thirds were UD graduates.

Then UD President Patrick Harker thanked Castle for his long and close relationship with UD and said the papers would illuminate Castle's work on high profile committees and on policies to which he had an abiding commitment. “Our students and faculty, along with scholars from across the country, will be indebted to Congressman Castle for the unique insight these papers provide into U.S. policy development,” Harker said. “It is impossible to match the value of primary sources like these, and we couldn't be happier that his [Castle's] legacy will have a home here.”

Susan Brynteson, then vice provost and May Morris Director of Libraries, said, “Over the years, Mike Castle's platform has been proven leadership, independent thinking, common sense solutions and bipartisan collaboration,” Brynteson said. “The UD Library is proud to be the home of Mike Castle's Congressional papers.” 

Later that year, Castle delivered the Commencement address in Delaware Stadium and was awarded an honorary doctor of laws degree.

Speaking to the Class of 2011, he urged the graduates to build on personal relationships and take a keen interest in what is going on across America and around the world.  “As you look around you today, you are most likely surrounded by the people in your life who matter the most -- your parents, grandparents, siblings, friends and teammates,” Castle said. “This is what I want you to hold on to. They are the basis of friendship and love, and also for success at work, in activities and in your community.” 

In more recent visits to the campus, Castle delivered the fifth annual James R. Soles Lecture on the Constitution and Citizenship in 2015, and he spoke in the University’s 2017 National Agenda speaker series, discussing past and present political divides.

Funeral services are scheduled Aug. 21-22 in Wilmington.

To read his official obituary or leave online condolences, visit Chandler Funeral Homes and Crematory.