The 51-year-old was in the dugout for the final time for the 3-1 derby triumph over Cowdenbeath on Saturday after it was confirmed he was stepping down to focus on commitments away from the game.
Manager Grant Murray heaped praise on his departing No.2, insisting Raith would never have ended their 20-year trophy drought by winning the Ramsden's Cup last season if not for Smith's influence.
"What [Paul] has done for me, firstly when I came here as a player, then as my assistant, was massive. Without him, things could have been very different," Murray said. "I can only thank him for everything he has done. I could not have [won the cup] without him. We don't have a replacement lined up."