William O'Brien (American football)
William Edward O'Brien (March 11, 1923 – December 1, 2000) was an American football coach and official. He was the seventh head football coach at the Southern Illinois University Carbondale, serving for three seasons, from 1952 to 1954, and compiling a record of 6–20. O'Brien was an official in the National Football League (NFL) for 18 seasons, from 1967 through 1983, officiating in Super Bowl X in 1976. He wore number 83 for the major part of his NFL career. He was also a professor at Southern Illinois University.
William X. O'Brien
Born in Clonakilty, County Cork, and christened 'John William', O'Brien moved with his family to Dublin in 1897, and quickly became involved in the Irish Socialist Republican Party (ISRP). O'Brien is described as "a very significant figure in the ISRP" by the historian of the ISRP, David Lynch. He was a member of the Socialist Party of Ireland, serving on its executive.