Shale pioneer and natural gas advocate Aubrey K. McClendon is gone, but his unbridled enthusiasm left a legacy of vast reserves of shale oil and gas throughout America and numerous civic and charitable contributions to Oklahoma City. These gifts will be enjoyed for many years to come.

The founder, chairman and CEO of American Energy Partners LP died last month in a fiery car crash in Oklahoma City a day after being indicted on charges of rigging bids for leases in Oklahoma while he was chairman and CEO of Chesapeake Energy Corp. It was a shocking and tragic climax to one of the most stunning careers in oil and gas this generation had seen.

During the peak of the shale gas boom, McClendon posed onstage with a promotional T-shirt at a Hart Energy DUG conference. He was a frequent speaker and advocate for unconventional resource development.

On the strength of his charm, savvy and forward-thinking, risk-taking approach to business, he and partner Tom Ward turned a $50,000 investment in 1989 into a multibillion-dollar company employing 13,000 people at its peak. Chesapeake was named to Fortune’s 100 Best Places to Work five years running.

The record of Chesapeake’s achievements is impressive: In its prime, the company had an enterprise value of $34 billion. It generated more than 30% of the growth in U.S. gas production over the five years to early 2012. It held nearly 19 trillion cubic feet equivalent (Tcfe) of proved onshore gas reserves, while also forming drilling company Seventy-Seven Energy, FracTech International and Chesapeake Midstream.

But the fortunes of this entrepreneur and his companies rose and fell on the volatility of commodity prices and an ever-larger hunger for capital, which led to outsized personal and corporate debt. At one time, Chesapeake was said to be the second-largest producer of gas in the U.S. yet was carrying more debt than ExxonMobil, an astonishing testament to the cause and effect of the company’s aggressive growth under McClendon’s leadership. He always swung for the fences.

Numerous times at investor conferences we heard McClendon joke that if you had invested in Chesapeake, you would have made a lot of money—but suffered a heart attack or two along the way.

The year 2008 illustrates the roller coaster that the man, the company and his investors rode. Although Chesapeake shares hit $70 in July, by October they were as low as $12.65, and McClendon had to sell 94% of his shares in a margin call as gas prices plummeted. That same year, Fortune dubbed him Mr. Gas, and he signed a $3.375 billion JV in the Marcellus Shale with Statoil—the first time an international oil company entered a U.S. shale play.

Statoil paid $1.25 billion in cash up front and financed the rest of its commitment by funding 75% of Chesapeake’s costs to drill and complete Marcellus wells. Through this and subsequent shale JVs, McClendon essentially paid off all his aggressively priced acreage and got someone else to foot most of the drilling bill, bringing in money from Total and CNOOC (China National Offshore Oil Corp.) as well. Even so, he continued to lease acreage in all the major plays except the Bakken, in turn necessitating the drilling of more wells (despite low gas prices) to hold those leases, and driving Chesapeake deeper into debt.

He was an enthusiastic—at times reckless—visionary and innovator, one of the top generals leading the campaign to develop natural gas supply in this country.

McClendon accepted Investor’s M&A Deal of the Year Award in 2011 for Chesapeake Energy’s JV with CNOOC in the Eagle Ford, which he said recycled trade deficit dollars back home from China.

The land grab

With his trademark optimism for the shales, he began what he came to call The Great North American Land Grab. Chesapeake had more than 15 million net acres under lease and a leading position in 11 of the top 15 unconventional plays. By virtue of its status as the most active driller in the country, McClendon bragged, Chesapeake had knowledge of almost every shale well being drilled.

From 2005 to 2007, as the industry began to grasp the potential size of the shale prize and that horizontal fracking was a game-changing technology, shale became a once-in-a-lifetime opportunity, setting off a frenzy of capital raising, leasing and drilling. McClendon and Ward sent hundreds of landmen across the country, usually driving up the price per acre to the dismay of other producers.

This history made the federal indictment that punctuated his career all the more ironic.

“Aubrey McClendon … indicted for keeping lease costs down. What delicious irony,” said Drillinginfo CEO Allen Gilmer in a blog post the day before McClendon died.

“Chesapeake was the first company to recognize the unconventional revolution as a land grab, and if every location was drillable, a case could be made for making a step-change valuation redetermination for what they could pay for leasing those minerals … until the ability to put together sizeable blocks was available only to the very best-capitalized, or those able to raise massive amounts of capital. Raising massive amounts of capital is at the very core of McClendon’s sweet spot … ,” Gilmer said.

“If anyone doubts that Chesapeake was the principal driver of value in unconventionals, watch what happened when Chesapeake departed the plays they were in.”

Advocating for gas

As supplies soared, McClendon began promoting more natural gas use. He was a founder of America’s Natural Gas Alliance and, in 2007, created the American Clean Skies Foundation. It was a sea change in thinking, because in 2002, with 882 rigs drilling for gas, U.S. producers still weren’t finding enough: Domestic production was down about 5%, according to a Credit Suisse First Boston analysis cited by Oil and Gas Investor. As a result, there was talk of importing LNG. But as the true potential of unconventional gas emerged, it upended the entire industry.

From then on, gas production rose steadily, even though the number of gas rigs decreased. McClendon responded by upping the ante on Chesapeake’s activity and adding more debt to fuel the increase.

In 2009, he met with Charif Souki, then-CEO of Cheniere Energy Inc. The company had built an LNG import terminal on the Louisiana coast based on the common wisdom of the day that the U.S. would eventually not have enough natural gas supply.

McClendon thought otherwise. He asked Souki if Cheniere might instead consider the idea of exporting U.S. gas. The rest is history, with Cheniere sending out the first shipment of U.S. LNG only a few weeks ago.

McClendon was never one to shy away from a fight. He placed full-page anti-coal ads in Texas newspapers when a Texas utility announced plans to build six coal-fired power plants in the state. He always stood up for his company and its strategies, for the industry and for the promise of abundant natural gas supplies.

The ride to the top was marred in late 2007 when a credit crunch, made worse by gas prices falling below $6/Mcf (considered a devastating price at the time), threatened Chesapeake’s fast-paced growth trajectory. In response, McClendon announced Chesapeake would cut its production by 6%.

His decision generated some unexpected fallout—Connecticut Gov. M. Jodi Rell sent an angry letter to Congress charging that Chesapeake and other producers were trying to manipulate the gas market to raise prices in an affront to consumers. She called for an investigation.

McClendon fought back, releasing a widely circulated letter to the governor defending himself, his company and the industry as providers of the benefits of natural gas to the nation. He said the letter’s “incorrect and reckless statements” indicated the governor lacked an “understanding of the natural gas market” and the role played by Chesapeake—at the time, the third-largest U.S. independent gas producer.

“Because of the efforts of Chesapeake and other American independent producers, natural gas prices have increased less during the past five years than the prices of many other commodities such as oil ... ,” McClendon wrote.

The following year, 2008, the Sierra Club announced its support for natural gas as a cleaner burning fuel than coal or oil. Executive director Carl Pope told Investor that while the Sierra Club still favored renewable fuels, it now understood the role gas could play in improving air quality. It was later revealed that McClendon had been a major donor to the Sierra Club.

American Energy Partners

McClendon’s shale land grab came at a cost—a heavy debt burden. In 2013, when iconic investor Carl Icahn took a prominent stake and restructured the Chesapeake board, McClendon was ousted from the company he had built.

Within hours of leaving Chesapeake, however, McClendon announced that American Energy Partners was open for business, with a billboard near the entrance to Chesapeake’s campus advertising that the new company was hiring. Jefferies & Co. once again helped him obtain capital to start anew, this time $1.7 billion in equity and debt commitments from The Energy and Minerals Group and First Reserve Corp.—one of the largest initial commitments for a start-up in E&P history.

In short order, McClendon was back on track with the same playbook, buying up assets in several shale plays in the U.S. (and abroad, for the first time). But he cleverly set up each play as its own company, with the view that they could be better managed, more flexible and eventually spun off as separate public companies or sold to other producers.

The management team of American Energy Partners has vowed to continue on with their plan, inspired by the innovation and business creativity of their founder, Aubrey McClendon.