Momo Barone grew up in Hell's Kitchen, in the same area as Eddie Paradise. He grew up around people like Peter Clemenza and was was also the best friend of soldato and later caporegime Nick Geraci. He was also the nephew of Salvatore Tessio. "Momo", as he was effectively called, got his nickname "The Roach" due to the fact that his hair was greased down and as hard as a roaches back.
After Geraci killed Tessio in 1955, Momo never learned of this. He was 'made' under Geraci with fellow soldier Eddie Paradise. He also befriended fellow Geraci soldier Carmine Marino. He was considered not to trustworthy because of his blood relationship to Tessio. However he was liked by Tom Hagen, and was given the job to kill the man who stole his watch.
He was considered Nick Geraci's closest aide, but after Geraci was deposed in 1961, he was considered a likely candidate for the role of caporegime. But Barone got imprisoned in the meantime and his best friend Eddie Paradise took on the role. It is implied he didn't mind much, but he was sore that nobody trusted him because he was "Tessio's Kid". During "vacation" given by the family he met Geraci on the run in 1963 and agreed to help him.
He was promised the title of consigliere by Geraci if he agreed to help. He fed Geraci info on Michael Corleones moves. After Geraci was killed at an ambush, so was he. The irony was that he was too weak to kill Geraci which would have proven his loyalty, but was then killed by lifelong friend Eddie Paradise by a gunshot to the head. His body was disposed of on the Fresh Kills Landfill site.