World Wildlife Fund Executive Director Russell Train in his office in Washington, D.C. on September 9, 1994. (Larry Morris/The Washington Post)

Russell E. Train, a former tax court judge whose awakening on safari sparked a new career in environmental activism, as head of the nascent Environmental Protection Agency and as the first president of the World Wildlife Fund’s American chapter, died Sept. 17 at his farm in Bozman, Md. He was 92.

The death was confirmed by Carter Roberts, the president and chief executive of the WWF-U.S. The cause of death was not yet known.

Mr. Train was widely regarded as one of the most important American conservationists in the past half-century. He helped to craft some of the nation’s enduring environmental laws and to establish the agencies that continue to shape U.S. environmental policy.

While environmental politics today often divides sharply along party lines, with Democrats pushing for greater environmental regulation and Republicans seeking to scale it back, Mr. Train embodied an earlier era in which conservatives embraced the label “environmentalist.”

The son of a Navy admiral and nephew of jurist Augustus Hand, Mr. Train was a Republican and self-described conservative appointed by President Dwight D. Eisenhower to the bench of the U.S. Tax Court in 1957. Around that time, he and his wife took two safari expeditions to East Africa. He shot an elephant and was chased by a rhinoceros. The experience proved momentous.

“There were harshness and brutality, thirst, and fear, and pain, and sudden death, but also peace and innocence,” he wrote of those early travels in “Politics, Pollution, and Pandas: An Environmental Memoir” (2003). “It was the earth in the springtime of life, when all seemed fresh and young. For us, it was romance pure and simple.”

He started an African wildlife foundation and, in 1965, left the Tax Court to take over the presidency of the Conservation Foundation, a nonprofit research and education organization.

Four years later, under newly elected President Richard M. Nixon, Mr. Train was named undersecretary of the Interior Department. In 1970, he became the first chairman of the Council on Environmental Quality, an advisory group serving the president and other top officials.

The EPA was launched in 1970 with William D. Ruckelshaus as its administrator. When Ruckelshaus left to take over the FBI during the Watergate scandal fallout, Mr. Train was tapped to lead the environmental agency.

He remained its steady hand through the end of the Gerald R. Ford presidency in January 1977 and was credited with helping shape some of the nation’s landmark environmental laws, including the Endangered Species Act, the Clean Air Act, the Clean Water Act, and the National Environmental Policy Act.

From 1978 to 1985, he led WWF-U.S., giving him a platform from which he could advocate environmental protections worldwide. He pushed for two landmark international conventions, one of which established the concept of World Heritage sites, and another of which regulates international trade in endangered species.

Thomas E. Lovejoy, a George Mason University professor of environmental science and policy, called Mr. Train “the key person in the Nixon-Ford years who built the modern environmental laws and institutions of the American government. His fingerprints were everywhere.”

Russell Errol Train was born June 4, 1920, in Jamestown, R.I., and grew up in Washington, where he attended the private St. Albans School. He was a 1941 graduate of Princeton University, which he followed with Army service during World War II.

He graduated from Columbia Law School in 1948 and became a specialist in tax law. He headed the Treasury Department’s tax legislative staff before his appointment to the Tax Court of the United States.

Survivors include his wife of 58 years, the former Aileen Bowdoin of Washington and Hobe Sound, Fla.; four children, Emily Rowan of Chevy Chase, Nancy Smith Gustin of South Dartmouth, Mass., Charles B. Train of Washington and Errol T. Giordano of Bedminster, N.J.; and 12 grandchildren.

Mr. Train backed President George H.W. Bush enthusiastically, serving as national chairman of Conservationists for Bush in 1988. He was a sharp critic of President George W. Bush, saying that the White House had repeatedly interfered with agency decision making and ignored scientific expertise in crafting environmental policy.

During the Obama administration, Mr. Train worked behind the scenes to shore up support for EPA Administrator Lisa P. Jackson and her ongoing effort to regulate greenhouse gas emissions linked to climate change. During a private dinner in 2009, Mr. Train told her she was well within her authority under the Clear Air Act to regulate carbon dioxide as a pollutant.

And he continued to come into the D.C. offices of WWF-U.S. every week up until just before his death, Roberts recalled. “He would prowl the hallways in a seersucker suit, poking the troops, and reminding people to do unconventional things to get things done,” he said.

Lovejoy recalled that Mr. Train, despite his establishment pedigree, was an iconoclast and had an uneasy relationship with Nixon. “My intent is to give the EPA a strong independent character,” Mr. Train declared in a news conference at the Council on Environmental Quality. “We will have a strong, vigorous enforcement policy.”

Mr. Train could be rebellious. He once sneaked in a reference to land use in one of Nixon’s State of the Union addresses, which the president failed to notice during an initial read-through. As soon as he had given the speech, Lovejoy recalled, Nixon asked one of aides in fury, “Who’s the son-of-a-[expletive] who put land use in that speech?”