Convicted murderer Gaspare Spatuzza received the reduced 12-year term after he helped police secure the other convictions related to the Cosa Nostra crime syndicate's blowing up of Falcone's car in an attack which used more than 500 kilogrammes (half a ton) of explosives.
The huge blast on a motorway near Palermo in Sicily also killed the judge's wife and three police escorts and sparked outrage around the world.
Giuseppe Barranca and Cristoforo Cannella were sentenced to life in prison for their role. Cosimo D'Amato received 30 years in jail.
Spatuzza provided crucial evidence about how the mobsters plotted to take their revenge on Falcone over his attempts to break up their syndicate.
He told a Milan court earlier this year that he had been responsible for around 40 deaths during his time in Cosa Nostra.
He is currently serving life in prison for his role in six bomb attacks in 1992 and 1993 but may well end up being released under Italy's system of reducing incarceration terms once individuals are no longer deemed a threat to society.
Two months after Falcone was murdered, another judge, Paolo Borsellino was killed by a car bomb. The two men have posthumously become national heroes, martyrs to the country's largely unsuccessful attempts to rid itself of the scourge of organized crime.
Both killings were ordered by Toto Riina, the Cosa Nostra "boss of bosses" who was captured the year after the slaying of the judges. Now 84, the gangster known as "the beast", is currently serving multiple life sentences in a maximum security prison.