The 4-1 victory adds to China's gold medal sweep in the sport so far at the Paris Olympics, following his teammates' earlier triumphs in the women's singles and mixed doubles.
Moregard had been on an incredible run after eliminating Fan's teammate and world-number-one Wang Chuqin.
In the bronze match, 17-year-old Felix Lebrun won France's first table tennis medal since 2000 to cheer the home nation.
The nail-biting final seemed like it could go either way in the first three games. Moregard was proactive in his attacks from the beginning, consistently landing the ball at tricky angles that prevented Fan from using his forceful forehand.
World champion Fan, determined to contribute to China's gold dominance and win the title he lost to teammate Ma Long in Tokyo, lost the first game 11-7 but held his ground in the second and third games, winning both 11-9.
Fan, arguably possessing the best backhand in the world, faced a resilient Moregard who played with good variety. However, the Swede's inconsistent use of the chop block cost him some valuable points and he lost the last two games 11-8.
Wang Hao, Fan's coach and twice an Olympic silver medallist himself, held his player up in celebration after the match.
Earlier, LeBron avenged the defeat suffered by his older brother, Alexis, who lost in the round of 16 to the same opponent, Brazil's Hugo Calderano, by winning 4-0.
