An Oregon man became the first person to traverse Antarctica alone without any assistance on Wednesday, trekking across the polar continent in an epic 54-day journey that was previously deemed impossible.

Colin O'Brady, of Portland, finished the bone-chilling, 930-mile journey as friends, family and fans tracked the endurance athlete's progress in real time online.

"I did it!" a tearful O'Brady said on a call to his family gathered in Portland for the holidays, according to his wife, Jenna Besaw.

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"It was an emotional call," she said. "He seemed overwhelmed by love and gratitude, and he really wanted to say 'Thank you' to all of us."

O'Brady was sleeping near the finish line in Antarctica late Wednesday and could not immediately be reached for comment.

The 33-year-old documented his nearly entirely uphill journey - which he called "The Impossible First" - on his Instagram page . He wrote Wednesday that he covered the last roughly 80 miles in one big, impromptu final push to the finish line that took well over an entire day.

Photo provided by Colin O'Brady, of Portland., Oregon shows him posing while traveling across Antarctica on December 26, 2018 Colin O'Brady / AP

"While the last 32 hours were some of the most challenging hours of my life, they have quite honestly been some of the best moments I have ever experienced," O'Brady posted.

The day before, he posted that he was "in the zone" and thought he could make it to the end in one go.

"I'm listening to my body and taking care of the details to keep myself safe," he wrote. "I called home and talked to my mom, sister and wife - I promised them I will stop when I need to."

Though others have traversed Antarctica, they either had assistance with reinforced supplies or kites that helped propel them forward.

In 2016, British explorer Henry Worsley died attempting an unassisted solo trip across Antarctica, collapsing from exhaustion toward the end of the trek. Worsley's friend and fellow English adventurer Louis Rudd is currently attempting an unaided solo in Worsley's honor and was competing against O'Brady to be the first to do it.

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Besaw said O'Brady plans to stay on Antarctica until Rudd finishes his trek, hopefully in the next few days.

"It's a small club," she joked. "His intention is to wait for Louis and have kind of a celebratory moment with the only other person on the planet to have accomplished this same thing."

O'Brady's trek was hardly his first time beating overwhelming odds.

Ten years ago, his legs were badly burned in a fire in Thailand and doctors told him he probably wouldn't walk normally again, reports CBS News' Dana Jacobson.

But he re-learned to walk, then run, before going on to win the Chicago Triathalon 18 months after his accident. In 2016, he became the fastest person to summit the tallest peaks on each of the seven continents.

O'Brady described in detail the ups and downs along the way since he began the trek on Nov. 3. He had to haul 375 pounds of gear largely uphill and over sastrugi, wave-like ridges created by wind.

"Not only am I pulling my ... sled all day, but I'm pulling it up and over thousands of these sastrugi speed bumps created by the violent wind," he wrote in an Instagram post on Nov. 12. "It's a frustrating process at times to say the least."

On Nov. 18, he wrote that he awoke to find his sled completely buried from an all-night blasting of wind and snow. That day he battled a 30 mph headwind for eight hours as he trudged along.

"There were several times I considered stopping, putting my tent back up and calling it a day," he wrote. "I wanted so badly to quit today as I was feeling exhausted and alone, but remembering all of the positivity that so many people have been sending, I took a deep breath and focused on maintaining forward progress one step at a time and managed to finish a full day."

On Day 37, or Dec. 9, O'Brady wrote about how much he's changed, along with a selfie in which he looks almost in pain, snow gathered around his furry hat.

"I'm no longer the same person I was when I left on the journey, can you see it in my face?" he wrote. "I've suffered, been deathly afraid, cold and alone. I've laughed and danced, cried tears of joy and been awestruck with love and inspiration."

Though O'Brady had initially thought he'd want a cheeseburger at the end of his nearly impossible journey, Besaw said her husband has been fantasizing about fresh fish and salad because he has mostly been eating freeze-dried foods.

As for what's next for O'Brady, who also has summited Mount Everest, Besaw said she's not entirely sure.

"We are just so in the moment celebrating this right now," she said. "Then we'll see what's next on the horizon."