Balotelli, a £19.5 million deadline-day deal from England, became an instant hero to the Rossoneri after scoring both goals on debut in a 2-1 win over Udinese.
The 19-year-old dispatched a first-half volley before slotting home the dramatic stoppage time winning penalty.
After the match, Galliani was full of praise for his new star, announcing Balotelli's signature would return the club to the top ranks of European football.
"His signing gives the perception that we have returned as a great Milan," Galliani said.
"This Milan, in attack, is similar to Barcelona. We don't have Messi but we have Super Mario Balotelli."