|First appearance||The Godfather Returns|
|Last appearance||The Godfather's Revenge|
|Created by||Mark Winegardner|
Consigliere (Geraci's faction)|
|Relatives||Salvatore Tessio (uncle)|
Role in the novels
The Godather Returns establishes Barone's backstory; he grew up in the Bronx alongside boyhood friend Eddie Paradise, and was nicknamed "the Roach" because his rigidly shellacked hairstyle seemed as hard as a roach's exoskeleton. He was a protégé of Peter Clemenza, the best friend of Nick Geraci, and the nephew of Sal Tessio.
After Geraci kills Tessio in 1955, Momo is "made" under him with fellow soldier Eddie Paradise. He also befriends fellow Geraci soldier Carmine Marino. Michael Corleone considers him untrustworthy because of his blood relationship to Tessio, but he is nevertheless widely liked within the Corleone family; Tom Hagen in particular trusts him enough to give him the job of killing a man who stole his watch.
Barone is Nick Geraci's closest aide circa 1956 to 1960. After Geraci's treachery is exposed at the end of The Godfather Returns, Barone is considered a likely candidate for the role of caporegime, but Paradise is chosen instead. The following novel, The Godfather's Revenge, implies that Barone doesn't hold a grudge for being overlooked, but he is angry that nobody trusted him because he was "Tessio's kid". Barone meets with Geraci, who is still on the run in 1963, and agrees to help Geraci in his bid to dethrone Michael Corleone and take over as Don.
Geraci promises Barone the title of consigliere if he agrees to help. Barone agrees, and feeds Geraci information on Michael Corleone's plans. Ultimately, both Geraci and Barone are killed while attending a meeting that had been supposedly arranged for Geraci to negotiate his bid for leadership. The meeting turns out to be a setup masterminded by Michael Corleone, who orders Barone to kill Geraci as a test of loyalty. Barone falters at the last minute, however, and is killed by his lifelong friend Eddie Paradise.