Overview
Carlo Rizzi is a fictional character in Mario Puzo's 1969 novel The Godfather. In the 1972 film adaptation, he was portrayed by Gianni Russo.
In the novel and film
Described in the novel as "a punk, sore at the world", Rizzi was born in Nevada and moved to New York City following trouble with the law. He befriends Sonny Corleone and in 1941, he meets Sonny's sister Connie at a surprise birthday party for their father, crime boss Vito Corleone. Rizzi and Connie marry in 1945. Vito disapproves of Connie's marriage to a small-time criminal who is not a full-blooded Sicilian (Rizzi's father was Sicilian but his mother was from northern Italy), but consents to the marriage on condition that they have a traditional Sicilian wedding.
Rizzi basks in the glory of marrying into the Corleone crime family. However, Vito instructs consigliere Tom Hagen to forbid Rizzi to have any significant knowledge of the family's inner workings and only to "give him a living". He operates a small sports book under the family's supervision, though he proves inept even at that.
Rizzi hates how his in-laws treat him, and regularly abuses and cheats on Connie to assert his own power over the Corleone family. When Connie complains to her parents, Vito refuses to intervene, presumably to punish her for her poor choice in a husband. In truth, Vito is outraged by Rizzi's behavior, but he feels powerless to act because Italian tradition forbids fathers to interfere in their children's marriages.
From Wikipedia (CC BY-SA 4.0).