Earl starred as a tailback at Kent-Meridian High School in Kent, Washington, southeast of Seattle, despite his 6 ft 5 in (1.96 m) 242 lb (110 kg) frame more typical of a lineman or tight-end.
In his senior season of 1972, Earl was voted the state's MVP both on offense and defense, and was also named Washington's Top Scholastic Athlete of the Year.
That spring he won the state title in the discus, and his toss of 192 ft 7 in (58.70 m) still stands as K-M's all time mark.
At the University of Washington in Seattle, Earl started as a tight end as a freshman in 1973, but once again he proved valuable when switched to fullback for his final two and a half seasons.
He played fullback, blocking for Walter Payton for three years before being switched once again to tight end, then finished his nine-year career with the Birmingham Stallions of the USFL.