Reader was born in Lawrence, Massachusetts, and served in the U.S. Army Air Corps during World War II.
In 1960, he joined the American Football League and officiated its first game, between the Denver Broncos and the Boston Patriots on September 9, 1960.
A 1996 inductee to the Central Catholic High of Lawrence Hall of Fame, Reader was part of some of the most historic moments of the American Football League.
Reader was also a back judge at Super Bowl I (1967) and III (1969), when those games were the World Championships between the AFL and NFL champions.
He was shown in an iconic image in the January 20, 1969, issue of Sports Illustrated, wearing number 42, with his arms raised signaling a New York Jets touchdown by fullback Matt Snell during the AFL champions' 16–7 win over the NFL champion Baltimore Colts in Super Bowl III.