The Dutchman, who is now in charge of Manchester United, spent three years at the Allianz Arena, and during that time opted to sell Demichelis to Malaga.
While reflecting on his time at the German club, Demichelis told Bild: "I achieved a great deal at Munich. I used my strengths to win a place in the first team.
"I became a fan of the club. I felt like a favourite son. But from the first moment Van Gaal arrived at Bayern the place began to stink."
Demichelis won the Bundesliga title and the DFB-Pokal four times during a seven-and-a-half-year spell with Bayern.