Antonio was Prince Mancini's right hand man for many years. While Carter Fontaine was in charge of tactical operations and evil deeds to scare the shit out of the Prince's enemies, Antonio was the logical and less ruthless one. Antonio almost never smiles; in fact he seems to get very little pleasure out of life. However he is a lightning calculator and a financial wizard. Furthermore, he is good at looking at the long-term picture. He is not a strong supporter of violence; he avoids it when possible, only because he has learned that is a more logical non-violent posture promotes the most long term success.

Antonio became primogen for clan Ventrue after Carter Fontaine was killed in February, 1998.

During the same month, Fade Horne made threatening, disrespectful comments toward Antonio via telephone, and demanded to see Antonio immediately. Suspecting Fade was on his way to assassinate him, Antonio arranged security people to ambush Fade when he arrived at Antonio's Hotel. Antonio hoped this would allow him to incapacitate Fade and bring him back to New Orleans to charge him with crimes. However, Fade fought his way through the security forces and caught up with Antonio. After a somewhat heated discussion, the two made peace. Something about some guns and money.