The South African, who guided the Springboks to their 2007 World Cup triumph in France, will make his debut as Fiji coach in a test against Japan in Tokyo next week.
He replaces Senirusi Seruvakula, who served as interim coach following Mick Byrne’s departure in April.
"Jake brings something that very few coaches in world rugby can claim -- the experience of leading a nation to Rugby World Cup glory," Fiji Rugby Union Chairman John Sanday told a press conference with White on Tuesday.
"We are not going to Australia simply to make up the numbers. We are going there with a determination to compete and challenge expectations, and demonstrate what Fiji can achieve when world class talent is supported by world class preparation."
Fiji, ranked 10th in the world, have been drawn in Pool C with Argentina, Canada and Spain. They reached the quarter-finals of the last World Cup in France in 2023, losing 30-24 to England.
The Fijians have had a disappointing 2026 season so far, losing the Pacific Nations Cup final to Japan last month following successive defeats by Wales, England and Scotland in the inaugural Nations Championship.
White has coached mainly at club level since departing as Springboks coach after their World Cup win, having stints at French club Montpellier and the Canberra-based ACT Brumbies.
In his last coaching role, White took the Bulls to three United Rugby Championship finals in his five years at the team but lost them all.
The 62-year-old departed the Bulls after last year's final defeat by Leinster, saying the Pretoria outfit needed a new voice.
He said on Tuesday he would relocate to Fiji and spend time with Super Rugby Pacific team Fijian Drua while watching local club competition to try to identify new talent.
"I'd like to say we want to have the best-prepared group of players ever to go to a World Cup. That'll be our challenge," he said.
His immediate task will be to rebuild Fiji's confidence before they meet Japan.
"To be fair about the Fijians, they have lacked a bit of confidence this year," he said.
"Technically, working on game management, that's one area.
"The theory for me is we want Fiji to play like Fiji but just give them a little bit more structure, a little bit more formation."