Edson Tavares was last year sentenced to 10 years for the acid attack and eight years for stalking in two separate trials.
The two convictions meant the Cape Verde native would serve a combined term of 18 years in prison.
However, his defence lawyers argued that the two charges should be combined in one case, with the aim of reducing his overall sentence.
The appeal court in Bologna agreed to combine the cases and ruled that Tavares should serve 15 years, five months and 20 days.
Tavares attacked Notaro on January 10, 2017, after police issued a restraint order against him.
He doused Notaro in hydrochloric acid, causing severe scarring and permanent damage to her left eye.
The aspiring model and singer had to undergo several operations to reconstruct her face and was unable to return to her day job as a sea lion trainer for months.
Since the attack, Notaro has become a prominent spokesperson on violence against women.
Notaro’s lawyer, Alberto Alessia, said his client didn’t want her attacker’s jail term reduced but she was nonetheless happy with the verdict.
“Gessica is satisfied from a human point of view and me from a judicial view,” Italian daily La Repubblica quoted him as saying.
