Alberto Falcone was one of the sons of Carmine Falcone, born into wealth of a criminal empire. However, he received little respect from his family, ignored by his father and sent to Oxford for college.
Throughout the events of "Batman: The Long Halloween", various Gotham City criminals were murdered by a mysterious serial killer known only as Holiday. At first the murdered criminals were connected to Falcone. "The Irish," a gang of Irish hitmen for hire, were all put under the payroll of Falcone to kill then District-Attorney Harvey Dent by blowing up his house. Later, on Thanksgiving, they were all murdered in a hotel banquet room as they sat down to eat Thanksgiving dinner. By Christmas, Milos Grappa, the long-trusted bodyguard and consigliere to Falcone, was murdered in front of the Don's building. It initially seems to be the work of one of Falcone's rivals. On New Year's Eve, however, Alberto was apparently killed by Holiday during a party on board Falcone's yacht. His body was found and identified by his grieving father and Jasper Dolan, the Gotham City coroner.
During the next few months Holiday started killing members of Sal Maroni's mob. This led to massive tensions between Falcone and the Maronis, forcing Falcone to employ "freaks" such as the Riddler and Poison Ivy to stabilize his empire. A large number of Maroni's guards, patrons, and business associates were killed alongside some of Falcone's guards at Maroni's only "legit" business; an Italian restaurant. Another amount of Maroni's men were assassinated at Maroni's safe house on St. Patrick's Day, just before Falcone's daughter could go there and pull a hit on them herself. On April Fools' Day, Riddler was attacked but left unharmed. It is made clear the killer could've killed him if they had wanted to. The place where Holiday's guns were made and bought was located in Gotham's Chinatown neighborhood, but the Chinese gun-maker was found murdered inside his shop on Mother's Day.
One month later on Father's Day, Maroni's father and founder of the Maroni family, Luigi Maroni, was shot and killed in his tomato garden. During the Independence Day celebrations, Jasper Dolan, the coroner, was found dead at the Gotham City Docks with two bullets to the chest. Carmine Falcone's sister, Carla Viti, launched an investigation of her own into Alberto and her son Johnny's deaths, only to meet Holiday at the coroner's office and get shot to death on the day of what would have been the Roman holiday, the Feast of Lupercal.
On Labor Day, while Salvatore Maroni was being transported to a safer area after brutally scarring Harvey Dent in court with acid, Alberto Falcone appeared from nowhere and killed Maroni with two shots to the head. He was arrested by James Gordon after Batman gave him a brutal beating that left him with no feeling in one arm, several bruises, and a bloody mouth.
Alberto later admitted to committing all of the Holiday murders, including that of his cousin, Johnny Viti. His father offered to use his influence to free Alberto, if he only admitted to killing Maroni. But Alberto refused, smugly saying that his new reputation as Holiday made him much bigger than his father and all the gangsters in the mob put together. He was convicted by the jury and sentenced to the gas chamber. Although Alberto initially received the death sentence, the Falcone influence allowed him to instead plead insanity. He was imprisoned in Arkham Asylum instead, across the hall from the Calendar Man, another holiday-obsessed villain who was afraid that Holiday might overshadow him. Carmine Falcone was later shot in the head by Harvey Dent, who had recently turned to super-villainy and become Two-Face.
During the "Batman: Dark Victory" storyline, Alberto Falcone was released from Arkham with aid from D.A. Janice Porter, Dent's replacement, despite Gordon's recommendation that he remain in Arkham. Alberto was now under house arrest in his family home outside Gotham, with his brother Mario and sister Sofia Falcone. A tracer was attached to his leg in order to prevent an escape. While in the house, Alberto is manipulated by Scarecrow and Calendar Man into believing that he is being contacted by the ghost of his dead father; the Scarecrow, a former psychologist, determined that Alberto was most afraid of his father, and the Calendar Man posed as the Roman's 'ghost' to permanently eliminate his 'rival'. The gun from the Holiday murders was soon left in his possession, which he used to save Sofia from The Joker. On Carmine Falcone's birthday, a second gun was given to Alberto, to kill Sofia with in order to usurp powers of the five crime families (actually a part of Two-Face's plan to destroy the crime families). Alberto nearly killed her in a Holiday-style shooting, but ultimately stopped himself.
After murdering Janice Porter, Two-Face had her body left in Alberto's bed in order to trick Alberto into thinking he had killed her. This time Calendar Man and Scarecrow's fear toxins, bringing on Carmine's voice, tried driving Alberto to commit suicide. But Alberto knew that this advice did not fit in with his father's character, and he sees through the deception and exposes Calendar Man behind a one-way mirror. What happens next is never explicitly shown, but later events suggest that Calendar Man shot and wounded Alberto, at which point Sofia Falcone attacked Calendar Man, breaking his jaw and attaching her brother's electronic monitoring ankle collar to him, leaving him unconscious outside the Falcone estate for Batman and the authorities to find. (Gordon and Batman appear doubtful that Alberto could have injured the Calendar Man so badly himself, due to his limited physical strength and wounds). Sofia then took her wounded brother to a hiding place in the Falcone mausoleum. There Sofia criticized Alberto, recalling how Carmine had survived five shots to the chest. Alberto replies that he is not his father. Sofia, disgusted, agrees with this assessment and smothers him to death.