At Converse Judson, Parker was the offensive coordinator under coach Frank Arnold, as the team won the 1983 state championship.
In 1984, he took over head coaching duties at Marshall, guiding the school to a 56–27–1 record in seven years.
Parker was named the Texas High School Coach of the Year in 1988 and in 1990.
Moving into the collegiate ranks, Parker succeeded Corky Nelson at North Texas in 1991.
On November 9, 2009, Parker resigned as head coach at Texas Lutheran, where he had three more losing seasons.