Moya also won this event in 1996. His four titles is a tournament record, surpassing Thomas Muster.
After splitting the first two sets, Moya jumped out to a quick 4-0 lead in the third before Volandri, playing in his first ATP final, battled back and served for the match at 5-4.
But Moya won the next three games to claim his 14th victory of his career.
Volandri stretched Moya to four sets in the first round of the French Open in May.
Volandri was looking to become the first Italian to win an ATP event since Davide Sanguinetti won Delray Beach in March 2002. However, the 21-year-old will move into the top 50 on the ATP Entry Rankings.