Manny is best friends with Tony Montana who rises with him to the top of the cocaine business in Miami during the early 1980's.
Little is revealed about Manny's background in the film, but it is told that he and Tony Montana served time in prison and in the army while in Cuba.
At the beginning of the film, Manny and Tony make their way to America during the Mariel Boatlift in 1980. A month after being sent to Freedomtown, a detention camp, Manny opens the door to get him and Tony greencards and a job washing dishes at a small food stand called El Paraiso in Little Havana, Miami. Tony and Manny quit this job when they are offered a job by Omar Suarez an Underboss in the Miami-based Lopez Cartel, to meet a new Colombian connection at the Sun-Ray Motel in Miami Beach to pick up two kilograms of cocaine. Even though the deal goes awry, Tony manages to grab the cocaine while keeping the buy money. They then begin working for powerful yet affable drug kingpin Frank Lopez.
As Tony becomes more and more powerful, they eventually overpower Lopez, kill him (Manny pulls the trigger) and take over his empire. In the same scene he personally murders corrupt Miami Chief of Detectives, Vice Squad Melvin "Mel" Bernstein. It is during this time that Manny falls in love with Tony's younger sister Gina, which Tony angrily forbids. One night when Gina was out partying at the same place Tony and Manny were at, Tony angrily assaults a man making out with her and orders Manny to take her home. Gina angrily remarks about Tony's overprotectiveness. Manny retorts Tony is only concerned for her and a real man would give her a better atmosphere than the guy they roughed up, to which Gina replies how come Manny has not asked her out. Manny is clearly off put by her forwardness, surmising that Tony would make a bungee cord out of his guts if he dates Gina. Nevertheless, Manny begins a respectful relationship with Gina, albeit one they must keep hidden from Tony until the time is right. Their friendship is constantly strained as an often-coked up Tony fails to listen to his friend, who often offers financial advice and is placed in charge of security when Tony buys his mansion. After Tony begins having trouble with bank fees with the constant money that rolls in from the drug business, Manny suggests going to another person, Seidelbaum. While counting money and converting the millions to checks, Seidelbaum reveals himself as a cop, who arrests Tony for tax evasion. Tony is naturally angry at his friend, since unknowingly setting up the bust could end up costing Tony three years in jail. While Tony goes on a mission for Alejandro Sosa (another powerful drug lord who works with Tony) in New York, Manny disappears and marries Gina Montana. When Tony returns home and gets the address from his mother, he drives there and approaches the door. Manny answers, just as Gina appears at the top of the stairs. Enraged, Tony shoots Manny twice (although the second shot is edited out in the TV version) and kills him. Gina runs down the stairs and cries over Manny's body before telling Tony that they got married the day before. After going back to his mansion, Tony shows regret for killing his friend, but is killed shortly after by The Skull in a massive shootout.
In Scarface:The World Is Yours,after Tony gets back his mansion, Manny's ashes could be purchased in the exotics catalogue,and he's mentioned by Tony several times in the game with deep sorrow for his death,and by Coco that remembers Tony when he came to her bar with Manny