Paolo Gabriele's sentence was reduced to 18 months from three years because of mitigating circumstances, including that Gabriele had no previous record, had worked for years for the Holy See.
Gabriele also acknowledged that he had betrayed the Pope and was convinced, "albeit erroneously" that he was doing the right thing, according to Judge Giusppe Dalla Torre.
Gabriele was accused of stealing the pope's private correspondence and passing it on to journalist Gianluigi Nuzzi, whose book revealed the intrigue, petty infighting and allegations of corruption and homosexual liaisons that plague the leadership of the Roman Catholic Church.
More top news
At least 13 people are said to have been killed by a car bomb outside a Turkish stadium in an attack which reportedly targeted the police.
Syrian government forces are continuing a push for total control of Aleppo, while a reported 20,000 civilians left the city on Saturday.
Rex Tillerson is president of Exxon Mobil and has close business links to Russian President Vladimir Putin.