On the field, he wore uniform number 23, which was also worn by Jerome Boger, another African-American referee.
Grier attended college at the University of the District of Columbia.
In 1989, a year after becoming a referee, he oversaw the head coaching debut of Art Shell, the first black NFL head coach in the NFL's modern era.
His career ended abruptly during the 2004 NFL season when he was forced to retire due to a leg injury suffered during a series of games.
He was replaced by the back judge on his crew, Scott Green, who had previous experience as a referee in NFL Europe.