Mourinho quit Real three years before the end of his contract after a 2012-13 campaign without major silverware and has returned to former club Chelsea.
His stint in the Spanish capital was overshadowed by a series of ugly incidents and he alienated a significant section of Real's own fans when he benched club captain and goalkeeper Iker Casillas, a Spain team mate of Iniesta's.
"You just have to look at the facts," Iniesta said in an interview published in Sunday's edition of El Pais newspaper when asked if Mourinho had harmed Spanish football.
"Yes he damaged Spanish football, in general more harm than good," added the 29-year-old.
"But I don't like talking about that person at all. So if you don't mind we'll leave it at that."
Mourinho, 50, was an assistant coach at Barca in the late 1990s and has also managed Porto and Inter Milan.
The list of controversial incidents during Mourinho's three years at Real is long.
They include sneaking up behind Tito Vilanova, then assistant Barca coach, during a brawl and poking a finger in his eye, repeated complaints about refereeing bias, ugly clashes with journalists and Real officials and dark hints that Barca got favourable treatment from governing body UEFA.
In one of his last appearances at the Bernabeu, Mourinho was sent from the bench during the second half of last month's King's Cup final for furiously berating the referee.
He did not appear after the match, which Real lost 2-1 to city rivals Atletico Madrid, to collect his loser's award from the Spanish monarch.