Simon had five service breaks in a 6-4, 6-3 decision over Fognini in a match that took nearly 2 hours. Simon is now 4-0 versus the Italian.
It was the third victory for Simon at the Nastase Tiriac Trophy event. He previously won in 2007 and 2008. Sunday's win improved his record in ATP championship matches to an impressive 10-2.
Fognini, who was 2-5 in 2012 before the Romanian tournament, was appearing in his first title match.
It was far from a clean victory for Simon, who faced 12 break points, saving 10. In the second set Fognini had five break-point chances -- all in the same game -- but Simon won them all. Simon won his other three service games in the set at love.
Simon collected $95,000 for the victory, which pushed him past the $500,000 mark for the year and over $6 million for his 10-year pro career. Fognini took home more than $50,000 as runner-up.