Finocchio Barzini holds dual roles within the Imperial Capital's criminal hierarchy. He serves as underboss assistant to the Luciano Family while simultaneously leading his own secondary group, the Barzini Family, as its don. This positions him as a key manager of the city's underworld enterprises, with his operations dominating specific sectors like the slave trade and brothels.

His physical presence is striking and flamboyant. Long, vivid silver hair is typically secured in a ponytail, framing sharp facial features and piercing violet eyes. His attire exudes aristocratic theatricality, often a gaudy purple suit lavished with extravagant gold embroidery and a flowing cape, cultivating an aura of eccentric control.

Personality reveals a paradox beneath the theatrics. Dubbed "The Mad Clown," Finocchio balances overt charisma with calculated ruthlessness. His demeanor shifts abruptly from jovial banter to chilling threats, creating unease. He maintains power through a pragmatic, exploitative approach, engaging without hesitation in morally ambiguous or cruel activities, including direct involvement in the slave trade, orchestrating assassinations, and leveraging psychological intimidation. His intellect and grasp of human behavior make him adept at negotiation and manipulation, often causing others to underestimate his strategic acumen.

His relationship with Noel Stollen is defined by mutual psychological gamesmanship and wary respect. Their first encounter occurs during a transaction where Noel sells former party members Lloyd and Tanya Clark into slavery. Finocchio participates in negotiating their value, theatrically displaying disdain but agreeing to the sale. Noel successfully manipulates him into paying a higher price by inflating the slaves' perceived worth, an act that both irritates and impresses Finocchio. Recognizing Noel's cunning, he later offers him a position, which Noel declines.

Subsequent interactions blend alliance and rivalry. Finocchio witnesses Noel's duel against Koga, Albert Gambino's representative, which determines Gambino family leadership. He agrees to reward Noel for removing Albert, a Luciano rival. Following Noel's victory, Finocchio employs the criminal skill "Judgment," physically threatening Noel by extracting his heart as a test of resolve. Noel outmaneuvers him, cementing grudging mutual respect, though their interactions remain fraught with potential betrayal.

Later, Finocchio collaborates with Noel to organize a tournament advancing Noel's ambitions concerning Leon Frederick. Finocchio handles logistics like land acquisition and resource allocation while managing his crime boss duties. Despite initial reluctance, he becomes invested in the tournament's success due to Luciano Family benefits. Noel pushes him to aim for the Luciano hierarchy's top position, requiring rival eliminations. This forces Finocchio to confront choices involving loyalty and morality, revealing his darker, calculating nature as he plots against former allies.

His broader influence within the Imperial Capital stems from feared authority and strategic intelligence. Actions taken through the Barzini Family impact other characters and shape criminal events across the city. His reputation as a powerful, clever leader ensures his presence consistently affects the narrative trajectory.