Hamsik conceded that Coach Walter Mazzarri and President Aurelio De Laurentiis persuaded him not to join the San Siro side.
"I spoke with President De Laurentiis and then with Mazzarri," he told Guerin Sportivo. "Both of them explained to me why the club did not want to sell me.
"According to them, it would have been a mistake to join Milan. That has been invaluable advice.
"I am happy in Naples.
"The people love me and the fans appreciate me for what I am.
"The Coach is our secret weapon here. If, in these last few years, we have obtained some extraordinary results, it is thanks to Mazzarri.
"He makes everyone feel important."