[1] It is not known precisely when he joined the Mafia but according to pentito Gaspare Mutolo, he started off as a driver for Kalsa boss Tommaso Spadaro, whose nephew was Giuseppe Lucchese, who would go on to become Greco's best friend and accomplice in many murders.

During the Second Mafia War from 1981 until 1984, orchestrated by the Corleonesi, Giuseppe Greco carried out dozens of murders, often with his favourite weapon, an AK-47 rifle.

Greco gunned down Stefano Bontade, Salvatore Inzerillo, Pio La Torre and police officer Ninni Cassarà in 1985.

Greco and his accomplices would subsequently retaliate against Contorno by murdering many of his friends and relatives in an ultimately unsuccessful effort to flush him out.

He participated in the so-called "Christmas Massacre" when, on the afternoon of 25 December 1981, in Bagheria, three Mafiosi – including Giovanni Di Peri, the boss of Villabate – and an innocent bystander were murdered.

Marchese ran the so-called "Room of Death", a small apartment along the Piazza Sant Erasmo where victims were tortured and murdered before being thrown into vats of acid or dismembered then dumped out in the Mediterranean.

On 30 November 1982 Greco personally strangled to death Palermo boss Rosario Riccobono, the long-time ruler of the Partanna-Mondello family.

The Corleonesi invited Riccobono, Scaglione and three other men to a meeting in a country villa between San Giuseppe Jato and Monreale, and shortly after their arrival, they were separated and massacred by Pino Greco, Giovanni Brusca and their team of killers.

[6] One of his last crimes was leading a large hit squad that ambushed and shot to death police investigator Antonino Cassarà on 6 August 1985.

He was shot to death by his two fellow mafiosi and supposed friends, Vincenzo Puccio and Giuseppe Lucchese, although the orders came from Riina, who had felt Greco was getting too ambitious and too independent-minded for his liking.

Two years later one of Greco's accomplices and fellow Ciaculli killer Mario Prestifilippo was shot dead, reportedly also on Riina's orders.

Giuseppe Greco was given an in absentia life sentence as part of the Maxi Trial in 1987 after being found guilty of 58 counts of murder,[8][9] even though he was dead by then.