Tuivasa-Sheck scooped the prize, which is awarded to the best international player of the year, ahead of Tonga prop Siosiua Taukeiaho and New Zealand team-mate Jared Waerea-Hargreaves.
The 26-year-old returned from a 12-month international absence to help his country defeat Tonga 34-14 in the Oceania Cup Test and also featured in a 2-0 series triumph over Great Britain.
He also ran 167 metres and set up his team's only try in the 26-4 defeat to Australia.
Congratulations Roger pic.twitter.com/E4XNyVpvLg
