China's Zhang Jike wins gold
Zhang, the 24-year-old World Champion, closed it out in five games to win four games to one - 18-16, 11-5, 11-6, 10-12, 13-11.
"I'm very excited, it's my first time at the Olympics and it has been my dream to win the gold medal since I started playing," Zhang said.
"I feel like I have completed a mission. In table tennis there can only be one winner."
It is a third-successive Olympic final defeat for Wang, who stalled Zhang's march to victory by winning game four and putting up considerable resistance in game five.
"Everyone wants to win the gold, but I lost to a teammate so it's not so serious. I've done my best," Wang said.
"The first game was quite important. The others followed as a result of that."
Earlier Wednesday, Germany's Dimitrij Ovtcharov won a captivating bronze medal match against Chuang Chih-Yuan of Chinese Taipei.
Ovtcharov, the World No.12, triumphed four games to two in a 12-10, 9-11, 8-11, 13-11, 11-5, 14-12 victory.
In the women's singles Wednesday, China's Li Xiaoxia beat teammate Ding Ning in a controversial singles final.