Marial's heartwarming rise from a fearful kid who hid in a cave, fled his war-torn homeland and finally arrived in the United States as a refugee took another incredible turn Saturday.
Despite having no passport and officially no country — and at one time very little hope — the 28-year-old marathoner was cleared by the IOC to compete at the London Games under the Olympic flag.
"The voice of South Sudan has been heard," Marial told The Associated Press from his home in Flagtaff, Ariz. "The South Sudan has finally got a spot in the world community. Even though I will not carry their flag in this Olympic Games, the country itself is there.
"The dream has come true. The hope of South Sudan is alive."
Marial — who was born in what is now South Sudan, a newly independent African country that doesn't yet have a national Olympic body — was one of four competitors let in at the London Games as independent athletes. Three others from Netherlands Antilles also were allowed to take part under the Olympic flag, but the case of Marial was the first of its kind at the Olympics, IOC spokesman Mark Adams said.
"He's actually running times I'm told wouldn't get him a medal but could get him in the top 10 to 20," Adams said. "He's come from out of nowhere. He's done two times, one of 2:14 and one of 2:12. Amazing."
Marial posted the Olympic qualifying time in his first ever marathon last year after being a cross-country runner at Iowa State University. He will get a chance to test himself against the best in the world in the Olympic marathon on Aug. 12, the last day of the games.
But Marial has less than a week to get to London so he can march at the opening ceremony at the Olympic Stadium and be part of the first day.
"I think they (his entourage and backers in the U.S.) will move heaven and earth for him to get here for the ceremony," Adams said.
The IOC's executive board gave Marial a chance after he didn't qualify for Sudan, South Sudan or the United States under its rules. He's a permanent resident of the U.S. after arriving as a refugee when he was a kid, but doesn't yet have American citizenship.
He was ready to head out to train when he heard he could go to the Olympics.
"I was getting ready to go for a run," Marial said. "Wow. This is so exciting. It's hard to describe. I'm speechless. The body temperature is up. I have to train like an Olympian now."
He told AP he didn't want to represent Sudan because he lost 28 family members to violence or disease during the civil unrest that left the country devastated and eventually led to the south splitting from Sudan last year.
Marial said he'd ask his father — who still lives in South Sudan — to travel to the nearest city to watch him on TV if he got to compete at the Olympics.
Two decades ago, Marial escaped from the labour camp in Sudan when he was 8, running away under darkness with another child about a week after he was kidnapped by gunmen and forced to work.
The pair hid in a cave until dawn, he said, and then followed the path of the sun. Marial lived in Egypt before eventually reaching the United States.
"I used to hate running. I was running back home to save my life," he told the AP in an interview Friday.
But he was good at it, grew to like it, and now loves it.
At 16, Marial joined the Concord High School track team in New Hampshire after encouragement from a gym teacher who saw he never got winded during any sports activities.
"I think there's something that can make you tired," he said the teacher told him.
He earned an athletic scholarship to Iowa State, becoming an All-American in cross-country in his junior year.
Marial qualified, amazingly, for the Olympics in his first 26.2-mile event, running 2 hours, 14 minutes, 32 seconds at the 2011 Twin Cities marathon — inside the Olympic qualifying time. He has since run faster.
But despite obvious natural ability, he still needed help to go to the Olympics. On Friday, a U.S. senator from New Hampshire lent support to his bid.
Sen. Jeanne Shaheen sent a letter to the International Olympic Committee appealing for Marial to compete under the Olympic flag.
"When you hear about his amazing personal story, what he has overcome, you just feel like the Olympic committee ought to look at his situation and figure out a way to accommodate him," Shaheen said.
They did, and Marial can now run at the Olympics in London — and run as fast as he can for the right reasons.
Associated Press writer Bridget Murphy in Boston contributed to this report.