Born in Springfield, Ohio, Hillelson attended the public schools.

[1] He served as chair of the Republican City Central Committee of Independence, Missouri, 1949.

Hillelson was appointed Executive Assistant to the Postmaster General, Washington, D.C., from January 3, 1955, until his resignation September 22, 1955.

He was appointed acting postmaster of Kansas City, Missouri from 1957 to 1961.

He died on May 28, 2003, in Shawnee Mission, Kansas and is interred in Arlington National Cemetery.