Supervised by Kempthorne, Graybill obtained his PhD from Iowa State U in 1952. In 1961, at Colorado State U, he founded the statistical laboratory that bears his name. He was co-author with Mood of the 1963 textbook Introduction to the Theory of Statistics, which for many years was the recommended introductory textbook worldwide. In 1976 Graybill became President of the ASA after a contested election (an unusual occurrence—the loser was Kruskal).
http://www.stat.colostate.edu/statdepartment/statnews/stat2012graybillobit.html Fuller biography and photograph.