Not to dispute what was on wiki, in the Dallas News this am:
"George Allen Summerall was born in rural central Florida on May 10, 1930, after his parents had divorced. He was taken in and raised bby an aunt and uncle. They had a son named Mike.
"In those days, people liked to tell ethnic jokes, " Summerall told The News in 1997. "Invariably when they got around to Irish jokes, the characters would be Pat and Mike. My aunt and uncle just started calling me Pat to go with their Mike."