Tom P:
My friend Ken Macpherson was only the third pro in the history of Walton Heath, I believe, after James Braid and Harry Busson. Ken is now the professional emeritus and his assistant has taken over as #4.
However the longest tenure I know was that of the manager, professional and superintendent at The Links Golf Club, who had been there 55, 56 and 57 years when they closed the doors for good!