Former Colorado Governor and Denver Mayor John Hickenlooper announced Monday he's running for president.

After being laid off as a geologist in the 1980s, he opened the first brewery pub in Colorado and went on to get elected mayor and governor.

He's already visited key primary states with his PAC, and could be one of the only governors, small business owners, and scientists in the race.

Hickenlooper has been touted as a "pragmatic progressive."

Half a dozen current and former aides, friends, and strategists told INSIDER that Hickenlooper could mount a serious dark horse campaign for the Democratic nomination.

"Hickenlooper would be Trump's worst nightmare in a debate," the former chairman of the Colorado Democratic Party said.

In the late 1980s, Colorado was in the depths of the most severe economic recession it had seen since the Great Depression. Unemployment had reached over 9% by 1987, businesses were folding at higher rates than anywhere else in the country, and residents were fleeing the state in droves, the Denver Post solemnly reported at the time.

Things started looking up in Denver's lower downtown neighborhood, colloquially known as LoDo, when a number of new businesses opened up, including the Wynkoop brewpub — the first of its kind in the entire state.

"In October of 1988, things were so depressed. Everyone jammed into the Wynkoop because they were offering very cheap beer," remembered Patty Calhoun, a founding editor of Westword Magazine which was located across the street from the Wynkoop, in an interview with INSIDER.

"That was the moment I remember meeting this lanky, floppy-haired guy with big thick glasses who was John Hickenlooper, one of the partners," she recalled.

Hickenlooper arrived in Colorado after graduating from Wesleyan University in the early 1980s to work as a field geologist for an oil and gas company. But when the commodities market crashed soon after, he found himself out of a job.

After visiting a brewpub while on a road trip in California, Hickenlooper and a few business partners decided to open a brewery in Colorado. He spent hours at the public library learning how to write a business plan, and persisted even after being rejected for loans by 32 creditors.

Hickenlooper's unlikely success as a business owner helped him launch a victorious bid for mayor of Denver, which led to two terms as the governor of Colorado. "Axe Files" host David Axelrod has jokingly dubbed him "a politician as unusual as his name."

Now he's officially a candidate for the 2020 Democratic presidential nomination after announcing his bid Monday. He's considered a possible dark horse contender in the 2020 Democratic presidential race.

Since leaving the governor's office in January of this year, Hickenlooper has traveled to the early primary states of Iowa, New Hampshire, and South Carolina with his GiddyUp PAC — the name serving as a nod to his Western roots and guiding perpetual optimism.

Read more: Former Colorado Governor John Hickenlooper announces a run for president

The optimistic underdog

Hickenlooper is no stranger to the role of the underdog.

He grew up in a middle-class family in the Philadelphia suburbs during the 1960s, the youngest of four siblings. He learned the value of perseverance at an early age, losing his father to illness at the age of seven, and struggling with dyslexia in school.

"I always first turned to humor, making myself the butt of the joke. Over the years, I'd learned that if you're a gangly, insecure nerd and if you embrace it ... it can become a strength," he wrote in his 2016 memoir.

While Hickenlooper can sometimes downplay his own intelligence, friends and associates describe him as fiercely smart and inquisitive, often enlisting his staffers to argue the opposite side of a position when trying to understand an issue.

"He loved talking to anybody and everybody at the Wynkoop, and the wide-ranging discussions often became very spirited," Calhoun remembered. "At one point, he had a scheme to arrange a pulley over the bar that would hold a giant dictionary, so that debates, often with me, could be settled on the spot."

Hickenlooper's first involvement in politics was spearheading a campaign to stop the city of Denver from selling the naming rights of the famous Mile High Stadium, home of the Denver Broncos, to investment firm Invesco.

After running ads and commissioning polling in support of the Mile High name, the city eventually gave in and struck a compromise to call the stadium "Mile High at Invesco Field."

That effort brought Hickenlooper to the attention of local political figures including Chris Romer, a former state senator and son of former Colorado Governor Roy Romer, who helped convince the brewery owner to run for mayor.

"I very quickly realized he was a guy who understood the value of branding and had a natural instinct to succeed in the public sphere," said Romer.

Hickenlooper prevailed as the underdog victor in the 2003 Denver mayoral race that began with 9 candidates. Helen H. Richardson/The Denver Post via Getty Images

Hickenlooper began his mayoral campaign polling at just 4% in a crowded field of candidates with far greater name recognition. But his campaign relied on creativity and personality to make the candidate stand out from the pack.

Creative TV ads — including ones in which he rode off in a moped while wearing a fancy suit and went around the city filling up parking meters while vowing to bring "change" to Denver — helped introduce Hickenlooper to the voting populace.

Months later, he went on to win a landslide victory with 65% of the vote.

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One former Democratic strategist close to that campaign, who requested anonymity to speak candidly on the matter, told INSIDER that Hickenlooper's once-unthinkable electoral success came from conveying a clear vision of making local government run as well as his business.

"It wasn't the ads that sealed the deal," the person said. "He actually took a pen and paper to the budget, said how he would transform the city, and he had the business background to back it up."

A "pragmatic progressive" governor

After serving six years as a highly popular mayor, Hickenlooper beat the odds again when he successfully ran for governor of Colorado in 2010 and was re-elected in 2014 — two Republican wave years which swept hundreds of Democrats out of office throughout the US.

Hickenlooper was then tasked with the challenge of governing a purple state that in many ways was a microcosm for many of the conflicts playing out on the national stage. Colorado's voter registrations were more or less evenly split between Republicans, Democrats, and non-affiliated voters — and the state legislature was under divided control.

"Nobody should underestimate [Hickenlooper]," the strategist added. "He might be an 'aw-shucks' guy on the podium, but he is all business and understands how to build policies, and work with both sides of the aisle to move the ball forward."

Hickenlooper sips a New Hampshire craft beer called "The Gov'nah" at a campaign house party. AP Photo/Elise Amendola

As a 2020 candidate, Hickenlooper will once again face a tough uphill battle starting with low name recognition in a competitive field.

Already, some political pundits and analysts are divvying up the better-known 2020 candidates and contenders between "idealist progressives" such as Sens. Elizabeth Warren and Bernie Sanders and "pragmatic centrists" in the mold of Sen. Amy Klobuchar and former Vice President Joe Biden.

But associates of Hickenlooper say his record proves that pragmatic and progressive aren't mutually exclusive.

"I don't view him as a moderate," said Pat Myers, a former restaurant executive who served as Hickenlooper's chief of staff during his second term as governor and is now a senior advisor at GiddyUp.

"I think he's quite progressive, but he's a really a pragmatic guy. We would have a lot of issues that would pit one industry or one faction against another, and his motivation was to come up with a solution," Myers added.

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During his two terms as governor, Hickenlooper enacted many of the policies proposed by progressive Democrats. He oversaw the legalization and regulation of recreational marijuana, expanded Medicaid, and signed three items of gun control legislation into law following the 2012 mass shooting at a movie theater in Aurora.

"There's a fundamental difference between proposing a policy and actually executing it," Myers said. "At the end of the day, he will be one of the few people in the race who can show actual progressive accomplishments."

But his record as a mayor and governor also included reducing the size and influence of government in other areas.

Hickenlooper's dedication to fiscal responsibility was so great that while serving as Denver's mayor he overcame his fear of heights to film two commercials that involved him jumping out of an airplane in support of a statewide fiscal reform referendum.

During his terms in office, he slashed government spending to balance budgets, did away with hundreds of state and local regulations on private businesses, and devised a regulatory framework for oil and gas fracking — earning him strong praise from Republicans.

Romer adds Hickenlooper could gain additional credibility as a rarity in presidential races: a small businessperson. His specific business acumen could pose a contrast to potential billionaire presidential contenders — including former New York City Mayor Michael Bloomberg and ex-Starbucks CEO Howard Schultz, who tout their private-sector success but have been criticized as out-of-touch.

Not only was Hickenlooper laser-focused on balancing government budgets in office, but incredibly frugal as a businessman. Romer remembered how at the Wynkoop, Hickenlooper refused to run the dishwasher unless it was completely full.

"This is a guy who won't even waste 35 cents of dish soap and a little bit of water," Romer added. "He really understands the value of a dollar and what it means to have to make payroll every Friday."

But Hickenlooper's trans-partisan style of governance also led some critics to accuse him of being indecisive, and having no discernible political principles.

“He so wants to have it both ways, to ingratiate himself with both sides, that he ends up leaving everyone unfulfilled like they’ve been played," Colorado political analyst Eric Sondermann told Governing Magazine in 2014. He added Hickenlooper's "split the difference" approach could work against him among voters looking for someone with clearly-defined policy positions.

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Shortly before his 2014 gubernatorial re-election bid, one Republican strategist said Hickenlooper could "kiss Republicans goodbye" over his signing of gun control legislation.

He also alienated conservatives when he changed his position on the death penalty, telling KDVR-TV in 2014, "My whole life I was in favor of the death penalty ... but then you get all this information: it costs 10 times, maybe 15 times more money to execute someone than to put someone in prison for life without parole. There's no deterrents to having capital punishment."

Hickenlooper added, "I don't know about you, but when I get new facts, I'll change my opinion."

Democratic presidential candidate Sen. Kamala Harris talks with Hickenlooper, right, at the Story County Democrats' annual soup supper fundraiser, AP Photo/Charlie Neibergall

Progressives, for their part, did not appreciate his friendliness toward oil and gas companies. Hickenlooper has faced fierce criticism from environmental advocates, particularly over his support for fracking.

In 2016, the progressive group Common Dreams warned that Hillary Clinton picking Hickenlooper as her running mate would "weaken the modest progressive gains made during the DNC’s platform struggle," accusing him of being "in his own form of climate denial."

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"Trump's worst nightmare in a debate"

Rick Palacio, who served as the chairman of the Colorado Democratic Party while Hickenlooper was governor, predicted to INSIDER that with fewer discernible policy differences between the 2020 Democratic candidates compared to the Democratic field in 2016, voters may prioritize someone with "a clear track record of results."

"Americans have enough on their plate already," Palacio added. "They don't want to keep constantly second-guessing the person in the Oval Office."

While Hickenlooper has never run one negative ad in his entire political career and has stayed away from directly attacking President Donald Trump, associates say he could be a formidable general election opponent for the president should he win the Democratic nomination.

"Hickenlooper would be Trump's worst nightmare in a debate," Romer said. "He's self-deprecating, has a wicked sense of humor, and is actually a successful self-made businessman, unlike Trump who inherited all his wealth."