He was the Underboss  of the Falcone Crime Family, and as such he had a lot of leeway to operate his crew and run rackets for the family. He's a sadist who takes pleasure in torturing people, and he has his sights set on taking over the family and running it himself.
Planning the Takeover
In the summer of 1950, Rocco decided it was time to make his move on Falcone. He begins by having Joe Barbaro take out two of Falcone's men he claims are crooked and a third he says is planning to move on Falcone. It's likely these men were just people Rocco wanted out of the way before he took over.
Sensing that Barbaro will remain loyal to Falcone Caporegime Eddie Scarpa, Rocco decides to have him taken out as well by setting up an ambush at the Uptown Parking garage. The plan fails and Joe senses something doesn't add up, so he heads to the Garden of Eden to discuss these recent events.
When Joe arrives at the Cathouse and tries to discuss what's been going on, Rocco suggest they talk about it later and walks away. As he does, he instructs his men to make their move and he opens fire, hitting Falcone in the shoulder. Rocco then tells his men to finish them off as he leaves the building.
Eddie and Joe manage to fight their way out of the Cathouse and then follow Rocco to a construction site in Midtown where he meets up with the rest of his men. Eddie waits outside while Joe enters alone to deal with them. After a lengthy fight, he finally corners Rocco on the roof, who tries to warn Joe about Falcone before being thrown to his death, landing on the street below.
- Rocco's suit is very similar to the attire in the Vegas Pack.