Ronald Reagan once told an audience that Joseph Coors Sr. was always giving him advice. "The most recent was about this gizmo I have to wear in my ear," said Mr. Reagan, referring to his hearing aid. "He advised me, if I have trouble hearing, I should wear it in my right ear. That's Joe for you, he never wants to hear from the left."

Joe Coors, who died on Saturday at the age of 85, was definitely a man of the right. He was a free-market enthusiast who helped turn his grandfather Adolph's regional beer company into America's third-largest brewer. He was also an early supporter of Mr. Reagan, casting a ballot for the man who would be president in 1968, when Coors was a member of the Colorado delegation at the Republican National Convention. He went on to become a member of Mr. Reagan's trusted "kitchen cabinet."

Yet his most important legacy doesn't lie in the beer business or electoral politics, but in philanthropy: Coors spent millions of dollars making sure people would hear from the right. The conservative movement simply would not exist in the form it does today without the profound influence of Joe Coors.

In the early 1970s, a small group of beleaguered conservatives on Capitol Hill recognized that they would never compete with the Brookings Institution and the other spokes of Washington's liberal establishment as long as they lacked a think tank of their own. As it happened, Coors was looking for ways to promote conservative causes. He was already in Reagan's camp, but understood that a general needs an army. The conservative movement required an infrastructure of policy experts and communications specialists who could generate ideas and deliver research to lawmakers with speed.

A well-timed investment in a company bound for greatness will pay off handsomely over time, and one of the best investments Coors ever made was in the Heritage Foundation. In late 1972, Coors wrote the check that made the foundation's creation possible. From that initial $250,000 has sprung an organization with a budget this year of $32 million. Over the course of three decades, Heritage has done the spadework of translating conservative principles into conservative governance. This was an especially crucial project after President Reagan's election, because such a thing never had been tried before. Since then, the foundation has played key roles in debates over health care, missile defense, welfare reform, taxes, and the budget.

"There wouldn't be a Heritage Foundation without Joe Coors," says longtime president Edwin J. Feulner. The beer magnate's seed money is arguably the most consequential that's ever been spent in the world of public policy.

Yet Coors didn't merely underwrite Heritage. As a member of its board, he convinced the think tank that it had to function as a business rather than a charity. He demanded that it create an operating reserve, and also appreciated the supreme importance of marketing, even for merchandise as ephemeral as ideas. Just as Coors became the first American beverage company to pour its product into aluminum cans, Heritage became the first think tank to flood Congress with those eight-page "backgrounders" on the topic of the moment.

Coors was present at many creations, including those of the Free Congress Foundation, the Mountain States Legal Foundation, and Colorado's Independence Institute. National security was a particular interest, and Coors aided Edward Teller and others in starting a group called High Frontier that helped persuade Mr. Reagan to pursue the Strategic Defense Initiative (whose 20th anniversary is this Sunday).

Like many in his family, Coors did not seek personal publicity. "He was a soft-spoken guy who never wanted to be the center of attention," says Chip Mellor of the Institute for Justice. At a Heritage Foundation event honoring Margaret Thatcher in December, as 900 conservatives turned their attention to the former British prime minister, Ed Feulner glanced at his patron and saw a tear welling in the old man's eye. Coors leaned over, gestured to those who had assembled, and said, "Heritage is my legacy."

—Mr. Miller is a writer for National Review and the author of "Strategic Investment in Ideas: How Two Foundations Reshaped America," just published by the Philanthropy Roundtable.