Mr. Zinke’s portfolio includes not only the country’s 59 national parks but also millions of acres rich in coal, oil, timber and natural gas, as well as the management of land and services for 567 native tribes.
Here in the West, where officials like to say the interior secretary’s power is second only to that of the president, many are training a careful eye on Mr. Zinke’s past, searching for clues to how he will chart their future. While he has cast himself in an uncommon role — a conservative conservationist — his critics say he is less of a friend to the environment than he would like to think.
“I want to be optimistic, because he’s a Westerner,” said Chris Schustrom, 49, a Whitefish resident who was the ball boy for Mr. Zinke’s 1979 state championship football team and is now Montana chairman of the nonprofit conservation group Trout Unlimited.
“Ryan, he’s always called himself a Teddy Roosevelt Republican,” Mr. Schustrom said. “But his record has been inconsistent.”
Westerners angered by land restrictions are hoping that Mr. Zinke will help them peel back Washington’s grip on public acres. For miners, ranchers and politicians in resource-rich regions, the Obama years were a rough ride. President Barack Obama blocked new coal leases, imposed moratoriums on uranium drilling near the Grand Canyon and set aside 553 million acres for national monuments, more than any other president.
“I could not be more thrilled that Donald Trump selected him,” said Representative Jason Chaffetz, Republican of Utah, who has tried to transfer millions of acres of public lands out of federal control.
Mr. Chaffetz cited a stop he had made the day before in Emery County, Utah. “We talked about: ‘The war on coal is over. We’ve got friendlier, greener pastures ahead of us.’ And there is a great deal of optimism and smiles on people’s faces that we haven’t seen in years.”
Mr. Zinke (pronounced ZINK-ee) spent his childhood fishing cutthroat trout from Good Creek with his stepfather, John Petersen, and hitching joy rides on train car ladders, a habit he called “hooky bobbing.” His high school voted him class president three times, and he guided the Whitefish Bulldogs football team through an undefeated season during his senior year. At the time, Whitefish was still a one-stoplight town.
It was in Whitefish and as a Boy Scout, he has recounted, that he developed his admiration for Roosevelt, who put aside 234 million acres of protected land, saving redwoods and ancient rock formations even as detractors harped that the president imperiled states’ rights and hampered economic growth.
“I am an unapologetic admirer of Teddy Roosevelt,” Mr. Zinke said at a January nomination hearing before the Senate Energy and Natural Resources Committee, where he evoked Roosevelt on 10 occasions. “I fully recognize and appreciate there are lands that deserve special recognition and are better managed under the John Muir model of wilderness, where man has a light touch and is an observer.”
After college, at the University of Oregon, Mr. Zinke joined the Navy SEALs, serving for 23 years and solidifying a disdain for leaders he called “desk jockeys” who directed policies from Washington offices. In his 2016 book, “American Commander,” he wrote that front-line fighters were the ones best equipped to make decisions about everything from the battlefield to land management.
Mr. Zinke entered politics in 2009, serving two terms in the Montana Legislature, and became the state’s at-large representative in the United States House of Representatives in 2015. He splits time between Washington, Whitefish and Santa Barbara, Calif., the hometown of his wife, Lola. He has three adult children: Wolfgang, Konrad and Jennifer.
In office, Mr. Zinke has repeatedly said he is against the transfer of federal lands to state hands, bucking Republican colleagues who say Washington controls too many Western acres. In 2016, after federal land transfer was added to the Republican platform, he resigned as a delegate to the party’s national convention.
He has campaigned for more money for the Land and Water Conservation Fund, which uses energy royalties to preserve outdoor space. And in his nomination hearing, he disputed Mr. Trump’s claim that climate change is a hoax. Some hope that means he will focus on the effects of shifting temperatures, which have altered and stressed everything from the crucial Rocky Mountain snowpack to the habitat of a rabbitlike mammal called the pika.
“When my family and I have eaten lunch on Grinnell Glacier, the glacier has receded during lunch,” he said of Glacier National Park, where the number of ice sheets has dropped to 25 from 150 in 1850. “Climate is changing; man is an influence. I think where there’s debate on it is what that influence is, what we can do about it.”