He delivered a pointed message after the incoming Real Madrid coach was spotted scouting the France international at Saturday's DFB-Pokal final in Berlin.
Mourinho attended Bayern Munich's 3-0 victory over VfB Stuttgart at the Olympiastadion as a guest of Stuttgart sporting director Fabian Wohlgemuth — a meeting facilitated by super-agent Jorge Mendes's agency GestiFute.
Sky Germany journalist Florian Plettenberg first reported that Mourinho's primary purpose was to monitor Olise in person ahead of his expected appointment at the Bernabéu.
Hoeness did not hold back when asked for his reaction on Saturday evening.
"He can keep five eyes on Olise — he won't get him. He remains unsellable. I hope I don't run into him, because he could have saved himself the trip from Madrid."
Olise, 24, has been extraordinary this season. He registered 22 goals and 30 assists in 52 competitive appearances for Bayern, helping the club win the Bundesliga title under Vincent Kompany and complete a domestic double with the cup victory over Stuttgart. His contract runs until 2029 and contains no release clause. Bayern sporting director Max Eberl has repeatedly stated in recent months that selling Olise is not under consideration.
Liverpool and Barcelona have also been credited with strong interest, with Liverpool legend Steven Gerrard publicly urging his former club to pursue him.
"All day long," Gerrard said when asked if Liverpool should move for Olise, before acknowledging the difficulty. "Why would he leave Bayern? He looks like a really happy kid, settled. I don't think he's going anywhere."
Olise joined Bayern from Crystal Palace in the summer of 2024 for a reported fee rising to £50 million. He is named in France's World Cup squad for the tournament in North America.
Mourinho can look as long as he likes. Bayern's answer will not change.