Marial fulfilled the A-qualification standard for the marathon in October 2011, allowing him to participate in the Olympic marathon event at the 2012 Summer Olympics. as prior to the games, South Sudan had yet to form a National Olympic Committee and seek full recognition by the
International Olympic Committee (IOC), which would have allowed them to send a team and compete under the
flag of South Sudan. Marial holds
permanent resident status in the
United States, but not
citizenship. The National Olympic Committee of
Sudan offered to allow Marial to compete as a member of the Sudanese team, but he rejected this offer, saying, "It's not right for me to do that. It's not right for me to represent the country I refuged from." He went on to say, "If I ran for Sudan, I would be betraying my people. I would be dishonoring the two million people who died for our freedom." However, his travel documentation did not reach him in time, and so he could not march in the
opening ceremony on 27 July. His personal best is 2:12:55. He competed at the 2012 Olympics using his adopted name of Marial, which was the surname of his uncle. However, he has since reverted to his birth name. ==2016 Summer Olympics==