At the beginning of Mafia, Thomas Angelo is presented as an ordinary taxi driver, who happens to be in the wrong place at the wrong time, and is involved in a mobster car pursuit. He joins Salieri's mafia & goes up in the ranks while doing jobs for the Don. He also starts leading a life of luxury while doing jobs for Salieri. He makes friends in the mafia, and he falls in love with Sarah, the bartender's daughter, who he marries eventually. When assigned with killing one of his best friends, Tommy breaks the Omerta and lets him slip away, action which Salieri finds out and tries to take Thomas out. He manages to kill Paulie, one of his former best men and Tommy's best friend, but Tommy survives & gives evidence against him & his organization. Tommy starts a whole new life along Sarah & their girl, and gets into legal business.
In 1951 Thomas is living in Empire Bay under the federal witness protection program and is an elderly man. In a strange twist of irony he meets his final fate when he is murdered by Mafia II's protagonist Vito Scaleta and his partner Joe Barbaro who are given a contract for his life by Falcone Capo Eddie Scarpa. Vito is given instructions to say one thing to Angelo before he pulls the trigger and they are the last words he hears. "Don Salieri sends his regards."