Momota is the reigning world champion, Asian champion and world number one and he can now add success in badminton's oldest tournament to his glittering CV.
The 24-year-old held his nerve to win 21-11, 15,21, 21-15 against Denmark's Viktor Axelsen.
"Winning this tournament has been a dream from my childhood and having won this it is a really big moment in my life, and gives me a lot of confidence," Momota said.
"The second game I played defensively against some very powerful shots from Viktor but in the final game I knew I couldn't carry on like that.
"So I didn't play particular tactics I just gave all I had and did my best."
Momota hopes his success can inspire more Japanese players to excel at the sport.
"I hope this win will help raise the badminton level in Japan. I'm going to keep improving myself so that everybody can be helped along with me," he added.
The women's singles title is back in Chinese hands for the first time in five years after Chen shocked defending champion Tai Tzu Ying.
The last Chinese winner was Wang Shixian in 2014, but 21-year-old Chen ended that barren run with a 21-17, 21-17 victory.
Tai had been looking for an historic hat-trick of titles and Chen admitted she didn't expect to come off court as a winner against such an illustrious opponent.
Tai previously had an 11-0 record against Chen and had only dropped one set in the tournament.
"I was over-excited. I didn't expect to win the Championship title in straight games," Chen smiled.
"When I express my joy I feel like I lose my physical composure, that's why I fell to the ground.
"I think I am more mature both mentally and physically compared to last year.
"I kept my pace on the court today, I think that's probably the reason why I won."