Westbrook graduated from Yale University in 1972, summa cum laude, Phi Beta Kappa, and with exceptional distinction in history. He received his PhD from Stanford University in 1981. Westbrook has taught at Scripps College, and Yale University. His first book, a reformulation and expansion of his thesis, John Dewey and American Democracy is considered the best intellectual biography of the influential pragmatist philosopher. Westbrook has been described by philosophers as "our best intellectual historian of pragmatism."