- "It's a shame I have to kill you Marco, you were a real pillar of the community."
- ―Aldo Trapani to Marco Cuneo[src]
He was known to be good friends with the members of the justice system and was officially not part of his family's business. He was seen as a well respected businessman, which helped him gain influence behind the scenes. In this respect, he was similar to his father Carmine, who was one of the few Dons who had never been arrested or even suspected of criminal activities.
Unofficially however, he was a violent and effective enforcer. He had been responsible for ordering the deaths of many Corleone family enforcers during the Five Families War, which led inadvertently led to the destruction of one of the Cuneo's racket chains by Sonny Corleone.
After the family consigliere, Luciano Fabbri, had been killed, Marco took revenge by eliminating several Corleone soldiers and was preparing for another onslaught when his heavily fortified position in Hell's Kitchen was hit by Aldo Trapani.
Trapani was under orders from Pete Clemenza, who ordered that Marco's death be made to look like an accident. Trapani obliged, flinging Marco into the nearby railyard. The authorities classed Marco's demise as an accident, and all witnesses were silenced.
Marco Cuneo is the last person to have his head on the Corleone's bounty list and Clemenza, the one who ordered the hit said that he's a "Big" target. His bounty is $7.500 and if the bonus is fulfilled, the player will get $37.500 as an extra. What's more: his hit gave the player most respect, the normal hit would give 15.000 points of respect while the bonus would grant an additional 150.000 points. His head gave the player the most respect points probably because of his reputation as a clean business man and a respectworthy citizen, but also a powerful warrior. So, Marco is presumably invulnerable and dangerous because he has support from police and citizens, that's why if someone managed to eliminate him, he would gain great reputation. His hit is given by Clemenza, right after player finished the Luciano Fabbri's hit.