He served as a first lieutenant in the Marines from 1952 to 1954, deployed to Korea and Japan. He studied at Yale with Edmund S. Morgan, the renowned historian of Puritanism and colonial life, who influenced him for over 50 years. After obtaining his doctorate. in 1961 he moved to the University of California at Berkeley, where he taught, and in the 1970s and early 1980s held various administrative positions.
In 1983, Professor Middlekauff became director of the Huntington Library in San Marino, Southern California, where he helped make resources more accessible to the public. He returned to Berkeley in 1988, saying he had failed to teach.
Graduate students of Professor Middlekauff at Berkeley included historians Ruth Bloch, E. Wayne Carp, Jacqueline Barbara Carr, Caroline Cox, Charles Hanson, Richard Johnson, Carolyn Knapp, Mark Cachia-Riedl, Charles Royster, and Bill Youngs.
Before writing “A Glorious Cause” Professor Middlekauff had published “Ancients and Axioms: Secondary Education in Eighteenth-Century New England” (1963) and “The Mathers: Three Generations of Puritan Intellectuals, 1596-1728” (1971) , which examined the development of theology and Puritan thought through the life and work of Ministers Richard, Increase and Cotton Mather, drawing on private papers and unpublished writings as well as sermons. He won the Bancroft Prize, one of the most prestigious honors in American history, in 1972.
In “Benjamin Franklin and His Enemies” (1996), Professor Middlekauff took an unusual approach, focusing on Franklin’s personal relationships and the emotions (especially anger) they aroused. He described Franklin’s conflict with Thomas Penn, the owner of the Pennsylvania colony (and the son of its founder); John Adams; and Franklin’s own son, William. The portrait that emerges is more complicated than the common views of Franklin as a smug bourgeois or a brilliant old man.
Working on the revision of “The Glorious Cause” aroused Professor Middlekauff’s curiosity for George Washington, who, he told John Fea in an interview with the online newspaper Current, “was not entirely satisfied.” . Edmund Morgan, he said, “strongly encouraged” him to “have another crack in Washington.” The result was “Washington’s Revolution: The Making of America’s First Leader” (2015).