Harper's family said he died Friday morning in an Ottawa hospital of cardiac failure due to diabetes complications.
He was 64.
"Elijah was a wonderful man, father, partner," the family said in a statement. "He will have a place in Canadian history forever for his devotion to public service and uniting his fellow First Nations with pride, determination and resolve."
Harper was a politician and leader for much of his life, but made his mark during the federal government's 1990 attempt to enact the Meech Lake accord, which had been crafted to win Quebec's signature on the Constitution.
Brian Mulroney, who was prime minister at the time, was pressing dissenting premiers to go along with the accord and gave them a deadline to approve it in their legislatures. Voting in Manitoba came late in the national debate.
Harper, then a Manitoba NDP opposition member, believed the deal gave his people short shrift.
Sitting in the legislature, holding an eagle feather, the soft-spoken former chief of the Ojibwa-Cree Red Sucker Lake band refused to allow rules to be waived to speed debate of the resolution. Pictures of Harper and his feather flashed across the country as he repeatedly said "No" in the face of enormous pressure and last-minute scrambling from federal officials.
The clock ticked down. Mulroney's deadline passed. Meech died.
"I stalled and killed it because I didn't think it offered anything to the aboriginal people," Harper explained.
It was a turning point for Canadian aboriginals.
"Elijah's commitment and dedication to asserting and upholding First Nations rights and recognition has helped lay the foundation as this hard work continues today," said Shawn Atleo, chief of the Assembly of First Nations.
"Elijah was soft-spoken, but his words resonated across the country and beyond," Manitoba Premier Greg Selinger said.
Eric Robinson, a New Democrat MLA who succeeded Harper in his legislative seat, now called Kewatinook, pointed out that his old friend was one of the few aboriginal MLAs anywhere in Canada at the time. Both Robinson and other aboriginal leaders realized that gave Harper a unique chance to ensure the concerns of his people were heard.
"It was a good opportunity because we had somebody in the Manitoba legislature that had that ability to say 'No,' said Robinson.
"That 'No' became noticed by the world, and I think it gave aboriginal people a sense of pride that we do have a place in Canadian society."
Some downplayed Harper's role in the failure of Meech.
Sen. Jean-Claude Rivest, who was adviser to then-premier of Quebec Robert Bourassa, said Harper was part of a broader push to derail the deal.
"He manoeuvred. But he's not the one responsible," Rivest said.
"It stemmed from the parliamentary strategy of the NDP and the Liberals in Manitoba. Mr. Harper was part of that."
Still, Harper was voted The Canadian Press newsmaker of the year in 1990.
Respect for Harper has never faded, said Aaron Cardinell, his longtime friend and business partner.
"He's very relevant for our people and a legend amongst our people. The communities everywhere still look up to him immensely. We still have a lot of tremendous respect for him in every way."
Social media echoed Cardinell.
"Elijah Harper was the first public figure who made me proud to be indigenous," tweeted Waubgeshig Rice, one of many who voiced their regard online. "Journey well."
Harper was the first status Indian elected to the Manitoba legislature, where he served from 1981 to 1992. That included a two-year stint as minister of native affairs in former NDP premier Howard Pawley's cabinet.
Harper's duties were interrupted briefly when he sought counselling for drunk driving.
He resigned from the legislature in 1992 and left the New Democrats a year later to run federally for the Liberals. He won a seat representing the sprawling northern Manitoba riding of Churchill.
Cardinell said Harper was not only a political inspiration, but a mentor to young aboriginals in the business community.
"He was inspirational at pursuing some of our goals that are to do with entrepreneurship and aboriginal business and to remember where we came from."
Harper was a "beautiful, kind-spirited man," said Cardinell, who balanced aboriginal spirituality with respect for his Christian upbringing.
"He really didn't have any ill will. He had a lot of respect for Canada and the system in Canada, even though it could be really tough on us and on our people."
Atleo also praised Harper's work bridging aboriginal and mainstream Canada.
"Elijah's drive and actions toward reconciliation will continue to be a legacy for First Nations and all Canadians as we move toward improved and renewed relationships."
Harper had some well-publicized financial problems. He was sued by creditors as well as his former wife. In 1992, two years after their marriage of 17 years collapsed, Elizabeth Harper said she had to go on welfare to supplement her meagre child-support payments for two sons and two daughters.
Harper had health issues as well. He became ill in the fall of 1994 when he was struck with a mysterious malady that doctors and native healers were at a loss to explain.
Family friend Darcy Wood said Harper had been dealing with kidney issues for at least the last five years. He had a kidney transplant late last year.
Still, Cardinell said, the news came as a shock.
"He was starting to recover (from the transplant). He was doing very well in the last couple of months."
He said Harper had been feeling ill Thursday night. He woke up about 1:30 a.m. Friday and told his wife Anita he needed to go the hospital, where he died.
He is survived by his wife, two children and four stepchildren. He was predeceased by a daughter.
Harper, one of 13 children, was intensely private. It took years before he would even reveal his age to interviewers.
Despite spending much of his life as a civil servant or politician, the man who was born on a trapline frequently sought solace from the pressures of political life by returning to the bush to hunt.
His biographer, Pauline Comeau, once said that although Harper wasn't acting on his own in 1990, that in no way diminished the significance of his deed.
"In that world it was a collective effort and he played his role," Comeau said in an interview shortly after her 1993 book "No Ordinary Hero" was published.
Following his active career in public service, Harper spent much of the rest of his life visiting First Nations, meeting with indigenous leaders across North America, working with charities and doing international humanitarian work.
"Elijah will also be remembered for bringing aboriginal and non-aboriginal people together to find a spiritual basis for healing and understanding," his family said.
— By Bob Weber in Edmonton
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