Injury cut short his French playing adventure but now, as the club's assistant coach to Vern Cotter, he is striving for the player/coach tournament double before joining Northampton Saints in the summer as attack coach.
"Wesley is one of the most talented players I have coached, but he is also one of the hardest workers," said King.
"He is always staying behind after training to hone his passing, tackling and kicking.
"He is a natural athlete but he appreciates that ability, no matter how rare, is not enough on its own to succeed at the highest level - you need the desire and the dedication."
And King is adamant that the collective desire is there for Clermont to be only the third French club to lift European club rugby's most coveted piece of silverware.
"Anyone who thinks that the Heineken Cup does not mean as much to French supporters as those in other countries only had to look at our semi-final against Munster in Montpellier," said King.
"The noise our thousands of fans made said it all, and to win the tournament for the first time would mean a huge amount to our region. Toulon will feel the same and it has the makings of a memorable final."