While he never pitched in the majors, Bob Castiglione (in today's Vault release for the first time) was twice on the Braves' 40-man roster and falls under the category of someone who went on to bigger and better things once his career ended.
He was a Rule V pickup from the Twins in 1968, but was offered back to them at the end of spring training. However, they declined to take him back and he remained in the Braves' chain. He was added to the 40-man roster in a conventional manner in 1970 (pitctured here), but again failed to make the club.
But that is but a footnote in the life of Castiglione, who rose to become the founder and CEO of LEAP Systems, Inc., a corporation that he continues to run in 2016.