Paolo Gabriele was accused of stealing the sensitive documents and leaking them to an Italian journalist.
The documents were photocopied by Gabriele and sent to Gianluigi Nuzzi, who used them for his bestselling book "His Holiness".
A three-year prison sentence for Gabriele was cut by presiding judge Guiseppe Dalla Torre to 18 months after taking into consideration Gabriele's apology to the Pope and his lack of a criminal record.
During the weeklong trial, Gabriele defended his actions, saying: "The thing I feel most strongly is the conviction of having acted out of visceral love for the Church of Christ and its leader on earth.
"I do not feel I am a thief."