Simplify the following text for a Grade 9 native English-speaking person.
Original: Michael Keller Ditka , Jr. ( born October 18 , 1939 , in Carnegie , Pennsylvania ) , is a former NFL player , television commentator , and coach .
Simplified: Michael Keller Ditka , Jr. ( born October 18 , 1939 ) , also known as `` Iron Mike '' , is a former American football NFL player , television commentator , and coach .