Mario Falcone first appeared in Batman: Dark Victory #1 and was created by Jeph Loeb and Tim Sale.
At some point after Carmine Falcone is murdered by Two-Face, Mario and Sofia visited their father's grave, giving him a posthumous birthday party with their cousin Lucia Vitti, Selina Kyle, and other high-profile Mafiosi in attendance.
By the time Lieutenant James Gordon and the police arrive, Mario and the rest of Falcone family have already fled.
[4] Sal Maroni's crime family begins robbing Falcone Imports, with help from Vitti and small-time smuggler Tony Zucco.
[7] On Columbus Day, Two-Face's gang attacks and kills all the Falcone Crime Family members, except for Mario, Alberto, and Sofia.
Mario later speaks with Gordon and Officer Julia Lopez about the deal that he made with Porter about the information revolving around Sofia's movements in exchange for protection.