Simplify the following text for a Grade 10 native English-speaking person.
Original: John Constantine Unitas ( juË Ë naÉ tÉ s ; May 7 , 1933 â `` September 11 , 2002 ) , known as Johnny Unitas or `` Johnny U '' , and nicknamed `` The Golden Arm '' , was a professional American football player in the 1950s through the 1970s , spending the majority of his career with the Baltimore Colts .
Simplified: John Constantine `` Johnny '' Unitas ( May 7 , 1933 â `` September 11 , 2002 ) , was a professional American football player in the 1950s through the 1970s .