The Irish gang were a group of Irish and Irish-American criminals from Hell's Kitchen.
In 1933, the O'Rourke brothers, Donnie, Sean and Willie, attempt to assassinate Luca Brasi. The plan is abandoned when Brasi and his gang arrive together rather than Brasi arriving alone. However, Willie decides to still attempt to kill Brasi but only wounds two of Brasi's men. This leads to Brasi murdering three of Tomasino Cinquemani's men before learning the Irish were responsible, after the Irish raid the Brasi gang's gambling den. Brasi retaliates by blinding Donnie and killing Willie.
In 1934, the gang attempt to hit Vito during a parade, this leads to a gunfight in which Stevie Dwyer attempted to shoot Vito, and was foiled by Bobby Corcoran, who accidentally hit Vito himself. During the shoot out Stevie Dwyer, Peter Murray, and Sean O'Rourke are all killed, while the others flee.
The rest of the gang were later single-handedly wiped out by Luca Brasi except for Corr Gibson. Brasi killed the Donnelly's in a slaughterhouse, Ricky was shot to death and Billy was thrown to his death. Though Bobby Corcoran was never a member of the gang, he was still murdered by his friend Sonny Corleone for accidentally shooting Vito.
- Donnie O'Rourke - founder and leader of Irish Gang
- Ricky Donnelly - second-in-command
- Willie O'Rourke
- Billy Donnelly
- Peter Murray
- Corr Gibson
- Stevie Dwyer
- Terry O'Bannion
- Digger McLean
- Sean O'Rourke