The 2019 world player of the year beat out nine other finalists for the illustrious honour, including former Fiji teammate Samisoni Viriviri, Fiji-born New Zealand international Tomasi Cama and Samoan sevens icon Mikaele Pesamino.
The diminutive playmaker made his debut for Fiji at the 2014 Gold Coast Sevens and has gone on to win three World Series titles, an Olympic gold medal in 2016, and is a three-time world sevens player of the year nominee.
"I'm very happy but I know I have a lot respect to the nominees like Cecil [Afrika from South Africa] and Tim Mikkelson [from New Zealand] - those two guys really stood the test of time in rugby," Tuwai said.
"To all the nominees, like [Tomasi] Cama, Perry Baker, Werner Kok, [Seabelo] Senatla, Samisoni Viriviri, I respect them and I love them as a rugby player and a human being.
"I'm very happy to receive this award on behalf of them, of Fiji, my family and on behalf of everyone who loves playing rugby."
Fiji coach Gareth Baber said 31-year-old Tuwai was a deserved winner who, despite his success, remained humble and dedicated to his craft.
"To find an individual of that quality is quite unique in a generation. I don't think I'm pushing it too far when you talk about him playing on the same team as [Fijian sevens legend Waisale] Serevi and doing himself justice the two of them together."
Despite standing just five feet seven inches tall, Baber said the former Fiji captain regularly defied his small stature with giant match winning performances.
"He's unbelievably skilful and he's almost acrobatic, gymnastic in what he can do on a rugby field. I think he's kept people entertained, not as just the way that he is able to do that to opponents but also in the way that he behaves in and around the series and he's a credit to his country and to the sport generally...
"For the country, having one of their sons crowned as the best of the decade, I think, is a phenomenal accolade. We're all so proud of him and very proud for me to see that as a country we have the ability to produce such quality individuals."
Tuwai grew up on the outskirts of Suva and, despite playing rugby from a young age, was a late bloomer - not making his international debut until seven months after his 25th birthday.
Baber said Fiji did not have the same development systems and processes that existed in many major rugby countries, which could lead to talented players falling through the cracks.
"What you get sometimes is missed individuals or late developers," he said.
"You get a very strong sense in the country there's lots of talent around playing rugby but they're not afforded the same opportunities - other than playing local tournaments- which enable individuals to suddenly jump up and release the potential that potentially they've grown since they were 15-16 years of age.
"Jerry happened to be 25 but there's nothing to say that for Jerry at the age of 18 or 19 that it would have worked at that stage. It's a different model, it's a unique model to Fiji but it's one that's worked and it's produced one of the best players of the last decade."
Among the other award winners, Black Ferns star Portia Woodman was named the Women's Sevens Player of the Decade, former All Blacks captain Richie McCaw was recognised as the Men's Fifteens Player of the Decade and Jessy Trémoulière of France was recognised as the Women's Fifteens Player of the Decade.