However, the Italian coach added that he was "grateful" that Madrid and Perez "thought of him" as the looked for a new boss.
"It was a decision I'd already taken, and even if other things can happen in life I'd say that I made the decision to stay at Juventus and respected what I'd said, without considering other options".
Allegri has since won four straight Scudetti with the Old Lady, marking a record seven consecutive Serie A titles in total, while also reaching the Champions League final in 2015-16 where the club lost out to Madrid. "I did it on the phone to [Madrid president] Florentino Perez because I had given my word to [Juventus] president [Andrea] Agnelli".
Allegri also hinted that he had been contacted by Chelsea regarding the possibility of replacing Antonio Conte at Stamford Bridge.
"I thanked Florentino for the offer but said I couldn't accept it out of the respect I owed to Juventus".
Real Madrid manager Julen Lopetegui has spoken out on his decision to not make a move for Eden Hazard in this summer transfer window. We need to improve what we started four years ago, and I'm happy to do it with this group of directors.
"I hope [he stays], but before we know for sure, we've got to await the end of the World Cup", he said. "Obliging players to stay does more harm than good".
According to news outlet Don Balon, incoming Real Madrid manager Julen Lopetegui does not want to sign the Chelsea talisman.