He’s skied to the North Pole, seen sunrise from the Himalaya Mountains, locked eyes with the deadly black mamba snake in the Okavango Delta. In a life full of pinnacles, Stuart H. Ellison, B.B.A. ’70, is still striving for the top.

“In 1988 a buddy said, ‘Let’s go climb Mount Rainier,’” Ellison says. At that time, the Wharton School M.B.A. grad had three young sons and a high-power career to tend. “I said, ‘Let’s talk about it next year.’ This guy replied, ‘You can say next year for the rest of your life.’”

He decided the friend was right. That June, Ellison summited his first peak. Even in the best conditions, Washington State’s Mount Rainier makes a challenging first climb. But that summer, he recounts, “There were nine feet of unseasonable snow. Nobody had climbed it in about three weeks—a couple of people had died the week before.”

He returned exhausted, dehydrated—and hooked.

“I’m attempting to stand on the highest point in each of the states in this country,” the retired commodities trader explains. So far he’s conquered 33—and adventured on every continent.

During two decades, Ellison, 60, has explored remote regions from Peru’s mystic Nazca Lines to Malaysia’s Taman Negara jungles. He’s tracked endangered gorillas in Uganda, pandas in their natural habitat in Woolong, China, and polar bears in the wilds of Canada.

“I shake every time I think about it,” he says of the 400-year-old prison he saw while retracing northern Ghana’s slave trade route. In Ethiopia’s National Museum, he held court with the glass-encased skeleton of 3.2-million-year-old hominid Lucy. And in April, Ellison embarked on his seventh African expedition—through Namibia, Swaziland, and Madagascar.

“I have had wonderful experiences,” he notes. “There have been tough times, though, when I was looking at my watch every hour thinking, when are we getting out of here?”

Not so one unexpectedly balmy winter day in 1998. Arriving blissfully atop Antarctica’s zenith, Mount Vinson Massif, in 15-degree weather, Stuart Ellison experienced yet another natural high few others have. “The sun was shining and there was not one ounce of wind,” he recalls. “I stood shirtless on top of Antarctica for a good 15 minutes.”

—Robin Shear