Antonello leaves his position as Inter's corporate chief executive with immediate effect.
It means president Beppe Marotta, who was sports chief executive, takes up the role overall to become the sole chief executive of Inter.
Antonello said: "I would like to thank everyone who has made these ten years in black and blue unforgettable. From employees to players, from coaches to managers, from sponsors to suppliers. On a day like this, my gratitude also goes to the great black and blue family, made up of millions of passionate fans.
"Working for this glorious club will be an indelible memory, which fills me with pride. I have dedicated every possible hour of my time to Inter and I am happy to have contributed to its history, starting from a difficult period until today, when the commitment of all of us has brought the club back to the top in Italy and Europe."
Marotta also said: “On behalf of the entire club and the Nerazzurri family, I would like to thank Alessandro for his great dedication to our club. On a personal level, I would also like to acknowledge his great human qualities that I have been able to appreciate since the first day I arrived at Inter.
"His work has undoubtedly helped all of us to begin this period of victories. Among the many trophies we have won together, I think that the day we won the Second Star will forever be a memory that unites us.”