His family said the 84-year-old former premier died Thursday of natural causes. In thanking doctors who had cared for him, they confirmed he had been ill for months.
“On behalf of all Canadians, Laureen and I offer our deepest sympathies to the family and friends of Peter Lougheed," Prime Minister Stephen Harper said in a statement.
“Today Canada lost a truly great man. Peter Lougheed was quite simply one of the most remarkable Canadians of his generation."
The Calgary-born lawyer and Alberta premier from 1971 to 1985 leaves behind a profound record of achievement and influence on public policy.
He took the reins of the fledgling Progressive Conservatives in 1965 and within six years had built a party that turfed a decades-old Social Credit dynasty and launched one of his own that continues to this day.
As oil prices shot to stratospheric levels in the 1970s, Lougheed became a provincial folk hero and a nationally recognized figure for his epic battles with Ottawa over control of Alberta’s black gold.
He kick-started petroleum diversification by nurturing oilsands development which now sprawls throughout northern Alberta, has brought the province billions of dollars and made it the economic driver of the country.
He fostered arts, culture and tourism and took the legislature into the modern age of communication.
He created a multibillion-dollar nest egg Heritage Savings Trust Fund as oil revenue began to pour in and championed medical research.
He helped patriate the Constitution and fought for a notwithstanding clause to ensure Canada would ultimately be governed by legislators and not the courts.
He championed bilingualism and in retirement spoke out against the Kyoto accord to control greenhouse gases, but urged caution over the environmental effects from unbridled growth of the oilsands.
He has served as mentor and role model for a generation of politicians, including current Alberta Premier Alison Redford.
This spring his endorsement of Redford and her policies during the general election campaign was seen as a pivotal boost that delivered another majority to the Tories.
Redford, who is attending a trade mission in Asia, issued a statement calling Lougheed a dear personal friend and "a powerful inspiration."
“He not only believed in a strong and united Canada, he believed that Alberta did not have to succeed at the expense of Canada, but as a proud member of a country working together," she said.
His dedication to public service did not end when he left office, she noted.
"He has remained an eminent and well-respected voice on matters of public policy, and I was honoured to have been the recipient of that advice over the years."
Former Saskatchewan premier Roy Romanow came to know Lougheed well during the constitutional debates of the 1970s and '80s.
"Overall, I think he goes down in my books as one of the giants of Canadian history," said Romanow.
"He always had foremost in his mind the development of Alberta, but also the development of Canada, because he saw the two going side by side. He really, really was an exceptional human being, a warm human being — just an exceptional Canadian."
Harper called him a "master politician, gifted lawyer, professional-calibre athlete and philanthropist" and said he was instrumental in laying the foundation for the robust economic success that Alberta enjoys today.
“He was a driving force behind the province’s economic diversification, of it having more control of its natural resources and their development, of Alberta playing a greater role in federation and of improving the province’s health, research and recreational facilities," the prime minister said.
Former Ontario premier Bill Davis recalled that he and Lougheed were both sworn into office in the same year and worked together for more than a decade.
"I respected him greatly for his strong sense of purpose and his unwavering commitment to policies that moved Alberta and Canada forward," he said.
"We were known to have a difference of opinion on occasion but I never questioned his integrity or his motivation. Working shoulder to shoulder on successfully patriating our Constitution was one of the proudest achievements we shared."
Edgar Peter Lougheed was born July 26, 1928, into an established family that had politics in its blood. His grandfather, James, had served in the Senate and in the cabinets of Conservative prime ministers Robert Borden and Arthur Meighen.
His father was a lawyer and, in 1952, 23-year-old Peter was also awarded a law degree. Two years later, he earned an MBA from Harvard. As an undergrad at the University of Alberta, Lougheed played football for the Golden Bears and the Canadian Football League's Edmonton Eskimos.
He married Jeanne Rogers of Forestburg, Alta., and together they would have four children.
Politics eventually proved irresistible to Lougheed. In 1965, at 36, he took over the Progressive Conservative party and rebuilt it from the ground up. He focused on strong candidates and constituencies, on one-on-one door-knocking and on the new medium of television, which was perfect for the telegenic Lougheed.
In 1971, the Tories won the provincial election and Lougheed set to work growing and diversifying the province.
In his pre-political days, he had spent time working in Tulsa, Okla., and saw a town where the oil resources were spent and the economy was in decline. That, he vowed, wouldn't happen to Alberta.
He raised oil royalties to underscore provincial control of resources and encouraged a foundation of Alberta-based financial institutions to reduce reliance on central Canadian banks.
He encouraged funding and research into extracting oil from the rich bitumen deposits near Fort McMurray.
To open up the business of government, Lougheed ordered that all daily proceedings in the house be recorded and distributed in Hansard. The same year he ordered daily TV coverage of debates. Both continue to this day.
He looked beyond business, too.
Under Lougheed's watch, the sprawling wilderness recreation area of Kananaskis Country west of Calgary was created.
Money flowed into the arts and there was support for the Banff Centre, performing arts venues in Edmonton and Calgary and the Edmonton Fringe Theatre Festival.
But it was his clashes with Ottawa on oil royalties that made him famous.
The oil price increases of the 1970s, spiked by turmoil in the resource-rich Middle East, sent money pouring into Alberta coffers. But the federal government wanted domestic prices kept below world levels and also wanted a share of the wealth.
Lougheed pushed back by refusing a deal with Pierre Trudeau, Liberal prime minister at the time, and later rejecting a similar one offered by Joe Clark and the Conservatives.
In 1980, Trudeau brought in the national energy program, a package of taxes and rules designed to funnel more resource revenues to Ottawa while keeping the domestic price below world levels.
Lougheed took it as a declaration of war.
In an impassioned TV speech, in which he accused the federal government of having moved right into Alberta's living room, he threatened to cut oil production. In March 1981, Alberta cut its daily output of 1.2 million barrels by 60,000.
Trudeau eventually relented and a face-saving deal was brokered that increased the price of oil and reaffirmed Alberta as the master of its own resources.
Trudeau's son, Liberal MP Justin Trudeau, issued his own condolences via Twitter on Thursday.
"It is with tremendous sadness that we bid adieu to a giant of Canadian politics," he wrote. "Peter Lougheed was a man of vision, integrity, and heart."
Lougheed also took on Trudeau over the patriation of the Constitution in 1982. The package included an amending formula which, in Lougheed's eyes, gave too much power to Ontario and Quebec and shortchanged the other provinces. He also saw the proposed Constitution as posing a threat to provincial resource ownership.
He began lobbying other premiers and eventually swung seven others against Trudeau.
“From the very outset we felt the federal government and the provinces are equal,'' he said long afterwards. “We just refused to take a position of being junior."
It was a brief encounter involving Lougheed at a first ministers meeting in the 1970s that sticks with Romanow most.
He was deputy premier of Saskatchewan at the time and was at the meeting in place of his boss Allan Blakeney. Romanow took on Ontario's Davis over his contention that oil companies didn't reinvest profits in oil exploration in eastern Canada.
The Saskatchewan position was to create an oil bank where profits from royalties could be saved and then spent on exploration throughout Canada. Trudeau stepped in. It wouldn't work, he said, point blank.
Romanow, the only non-premier at 24 Sussex that day, was caught flat-footed in the prime minister's glare. Lougheed bailed him out, turning the conversation back to the original debate with Davis.
"Afterwards, I walked up to premier Lougheed and I said, 'Peter, I want to thank you very much for saving my bacon with the prime minister. I think he had me in a chokehold on this particular argument,'" Romanow recalls. "He didn't see it that way and he had a very big laugh about it."
It was such a simple thing that, for Romanow, said so much about the man.
"Peter Lougheed always made you feel at home, made you feel as if your views were of importance. He would make suggestions. There was no ... command and control. There was always a very, very collegial dimension to his actions in public policy."
The Constitution was Lougheed's last big fight.
He won his fourth straight election that year and moved on three years later.
Since then the number of awards and commendations have been staggering. There are buildings, parks, scholarships and streets named in his honour. He was named to the Order of Canada in 1987 and the Alberta Order of Excellence in 1989. He was an honorary chief of the Cree and Blood First Nations.
This summer, the Institute for Research and Public Policy named him Canada’s best premier in the last 40 years.
In accepting the award, Lougheed told the audience: “Let’s keep building.”
Lougheed's family issued a news release saying they would hold a private service and that plans for a public memorial will be announced in coming days.
"Although he was known to many for his contributions to Alberta and to Canada, his first dedication was to his family," they said.
"He was a deeply caring and loving husband, father and grandfather. We will miss him terribly."