VERNAL, Utah — Bill Stringer leaned into the office of his top deputy here at the Bureau of Land Management one recent day to share his latest victory.

“We got upheld!” Mr. Stringer said, meaning his bosses in Salt Lake City had gone along with his staff’s recommendation to allow oil drilling near Desolation Canyon, a national historic site known for its pristine wilderness and white-water rafting. Despite objections from environmentalists, more oil wells would dot the huge stretch of federal land Mr. Stringer oversees.

Mr. Stringer, 55, who sports a goatee, rides a motorcycle and sometimes wears rock band T-shirts to work, is a little-known manager in an agency many Americans have never heard of, but he is arguably as powerful as many of Utah’s elected officials. As head of the bureau’s outpost in northeast Utah, he and his colleagues make decisions that have affected livelihoods and largely favored oil and natural gas companies eager to join in a national energy boom. The companies’ lobbying efforts extend beyond Washington to officials across the West, including Mr. Stringer here in Vernal, population 9,000.

The Bureau of Land Management, part of the Interior Department, is the nation’s biggest landlord, controlling 248 million acres, including nearly half the land in Utah. Charged with protecting public lands while exploiting their resources — for mining, drilling, timbering, ranching — Mr. Stringer’s agency has been at the center of a fierce battle in recent years as companies have sought to lease federal property and get drilling permits.