Riker was born in Des Moines, Iowa, and received his Ph.D at Harvard University in 1948. He took on a professorship at Lawrence University in Appleton, Wisconsin (then Lawrence College), where he published The Theory of Political Coalitions (1962). In 1962, he became the chair of the Political Science at the University of Rochester, where he remained chair until 1977, and remained active until his death.
He founded the now-mainstream field of positive political theory, which introduced game theory and the axiomatic method of social choice theory to political science. Bruce Bueno de Mesquita and Kenneth Shepsle in their Memoir write that "These have proved crucial to predictive tests for political theory."
Among other contributions, he is known for work on the theory and history of federalism and on something he called "heresthetics" - the art politicians use when they change political outcomes without changing peoples' underlying preferences, for example by manipulating the order in which decisions are made.
The William H Riker Prize is awarded bi-annually in his honor.
See also: Duverger's law