The AC Milan CEO has revealed the Italian club were priced out of signing the midfielder, saying the Bernabeu side's desired figure was "unthinkable" for the Serie A outfit
The Brazilian enjoyed immense success during a six-year spell at the Italian side but has struggled to leave a lasting impression in the Spanish capital, leading many to believe there was a possibility he would make a return to Milan.
However, Galliani has spoken out as to why the projected move failed to come to fruition.
"The story about Kaka is a closed chapter for me," he told Corriere dello Sport. "Real Madrid wanted €18 million [£15.5m] - a figure that given his age and salary demands made a deal frankly unthinkable."
While Madrid's asking price may have been steep for a 30-year-old who has had multiple injury problems, €18m [£15.5m] would still represent a massive loss on the €68m [£60m] that los Blancos paid for the Brazil international in 2009.
The Rossoneri may have missed out on Kaka, but they signed Mario Balotelli from Manchester City for an estimated €19m [£16.5m] in an attempt to give them more attacking options as they attempt to challenge for a Champions League place.