The loose-head joined the club in March on a short-term deal and is now contracted at Scotstoun until May 2017.
The 22-year-old, who has yet to play a competitive game for the club, has been selected in the Canada squad for this month's International Summer Series against Japan, Russia and Italy.
He made his test debut in November 2013 at the age of just 19 – becoming the youngest prop and the third youngest player to have represented Canada.
His second start for his country was against the Warriors in a pre-season fixture in Nova Scotia last August.
D'justice played for Canada in all four pool matches at last year's Rugby World Cup in England and was one of only five players to play in all four of Canada's 2015 Pacific Nations Cup matches.
He is the latest player to sign up at Scotstoun ahead of the new campaign with scrum-half Nemia Kenatale, winger Leonardo Sarto and hooker Corey Flynn due to arrive this summer, while prop Jarrod Firth and stand-off Rory Clegg are already on board.
Speaking to glasgowwarriors.org, Djustice: "I've really enjoyed the last few months in Glasgow and I'm very happy to be staying next season.
"There's a great atmosphere at the club and I've been made to feel very welcome.
"I spent a week out in Italy with the squad back in April which was a great experience and my goal when I return to Glasgow is to work hard for selection."
Glasgow Warriors head coach Gregor Townsend added: "Djustice has settled in really well and has impressed in training.
"He's really keen to learn and continue to develop over the summer when he plays for Canada and we're looking forward to him returning to Glasgow for pre-season training."