World number seven Tsonga, who currently occupies the eighth and last qualifying place for the London event in November, demolished the world number 28 6-1 6-2 in 50 minutes to clinch his second title this season after winning in Doha in January.
The Frenchman relied on his powerful first serve and his trademark forehand to quash his opponent, who did not get any opportunity to break back.
"I did great, it was good," Tsonga told French channel Sport in a courtside interview.
"I stayed focused all along, until the last second. I am very happy because it was the first time I have defended a title. I hope it will happen again," Tsonga, who has now won nine ATP title in his career, added.
Tsonga broke Seppi's serve in the fourth game with a passing shot and wrap the first set in 22 minutes.
Unlike his semi-final against Nikolay Davydenko, who made him work hard after a one-sided first set, Tsonga maintained his grip in the second set to quickly lead 4-0.
He then held to his serve and claimed the victory on his first match point with a last forehand winner.