Godfather II trivia

Troy Donahue as Merle Johnson
Dominic Chianese as Johnny Ola
Amerigo Tot as Michael's bodyguard
Joe Spinell as Willi Cicci
Bruno Kirby as Young Peter Clemenza
Frank Sivero as Young Genco Abbandando
Maria Carta as the mother of Vito Corleone
Giuseppe Sillato as Don Francesco Ciccio
Roman Coppola as Young Santino Corleone
John Megna as Young Hyman Roth
Julian Voloshin as Sam Roth
Larry Guardino as Vito's uncle
Danny Aiello as Tony Rosato
John Aprea as Young Salvatore Tessio
Leopoldo Trieste as Signor Roberto
Salvatore Poe as Vincenzo Pentangeli
Harry Dean Stanton as FBI agent
James Caan as Sonny Corleone (cameo)
Abe Vigoda as Salvatore Tessio (cameo)
Gianni Russo as Carlo Rizzi (cameo)
James Caan agreed to reprise the role of Sonny in the birthday flashback sequence demanding he be paid the same amount he received for the entire previous film for the single scene in Part II, which he received.
Marlon Brando initially agreed to return for the birthday flashback sequence, but the actor, feeling mistreated by the board atParamount, failed to show up for the single day's shooting; Coppola rewrote the scene that same day.
Richard Castellano, who portrayed Peter Clemenza in the first film, also declined to return, as he and the producers could not reach an agreement on his demands that he be allowed to write the character's dialogue in the film. Clemenza's role was subsequently filled by Frank Pentangeli.
Troy Donahue, in a small role as Connie's boyfriend, plays a character named Merle Johnson, which was his birth name.
Two actors who appear in the film played different character roles in other Godfather films; Carmine Caridi, who plays Carmine Rosato, also went on to play crime boss Albert Volpe in The Godfather Part III, and Frank Sivero, who plays a young Genco Abbandando, appears as a bystander in The Godfather scene in which Sonny beats up Carlo for abusing Connie.
Among the Senators in the hearing committee are film producer/director Roger Corman, writer/producer William Bowers, producer Phil Feldman, and science-fiction writer Richard Matheson.