"Luca understood our reasons and will stay, he is a great player and will continue to be an asset for Fiorentina," Della Valle was quoted as saying by Calcio Italia magazine.
"The player knows that he is essential for our future projects, I appreciate his understanding."
Toni was heavily linked with a move to Italian giants Inter Milan after Fiorentina were sanctioned for their role in the match-fixing scandal.
Fiorentina were initially demoted to Serie B, but they successfully appealed to return back to the top flight with a 19-point penalty.
The 29-year-old striker said he is looking forward to help the club in their difficult Serie A campaign next season.
"I had a chat with the President and that was enough, now I only want to play and try to achieve important results with Fiorentina," he said.
"I am totally convinced of my decision to stay here and am eager to start training with my teammates."