Walker was selected #1 overall pick in the 1968 NBA draft by the Detroit Pistons. He was also drafted #1 overall in the first American Basketball Association Draft by the Indiana Pacers. 1967 was the first year the NBA had abandoned its territorial draft (under the old draft, which granted an extra first round pick to be used on collegians within 100 miles of their professional team, Walker might have been selected by the Celtics and teamed with his mentor Sam Jones). Walker was also the final pick in the 1967 NFL Draft by the New Orleans Saints (the pick now known as Mr. Irrelevant), despite never having played college football; this makes Walker the only athlete drafted first by one pro league (two in his case) and last by another.