Arjan de Zeeuw of Wigan during their heyday either was qualified, or was part way to qualifying, as a doctor at the time his football career took off.
However, I think when he retired, he didn't pursue a medical career as intended: he went on to become a private detective/gumshoe type.
Shaka Hislop was, I think, an intern at NASA prior to football.
Sadio Mane has had some bad press this week, but he is fairly well known for giving large parts of his income away, building schools and hospitals in his home town.
I have to agree that Pat Nevin is a great pundit: probably the one I enjoy listening to most.