Jimmy Thoronka, 20, was his country's top 100m runner but did not return to his home country last year amid fears over the Ebola virus.
Homeless Thoronka says Ebola has killed his immediate family in Sierra Leone.
"Some days I get no food at all. I wash in public toilets and sleep in the park," he told the Guardian.
Thoronka arrived in Glasgow with his team-mates in July 2014 as the Ebola outbreak in his home country was declared a public health emergency. The death toll from the virus in Sierra Leone is now more than 3,500.
Up to 30 of the country's athletes wanted to extend their visas past September last year to stay in the UK - two were tested and given the all-clear for the disease on their arrival in Scotland.
Thoronka, described by Sierra Leone Athletics Association Abdul Karim Sesay as "a brilliant sprinter, a natural athlete and extremely fast", competed in one 4x100m relay at the games, but failed to win any medals.
He recorded a best time of 10.58 seconds for the 100m sprint before the competition.
In the Guardian interview, Thoronka claimed:
Thoronka won medals in African competitions and received the Sports Writers of Sierra Leone's best male athlete award in 2013.
He was the first athlete in Sierra Leone to carry the Queen's baton in the run-up to the Games.
Sesay said: "Many of the athletes have lost their families to the virus and I am looking after 10 of them at my house. It is a very difficult time."
"The picture here is very bleak.
"Jimmy's chances to become one of the world's greatest sprinters would be much better if he could stay in the UK and find someone to sponsor his training."
During the Games, Sierra Leone's chef de mission, Unisa Deen Kargbo, said that he planned to get the athletes back home as scheduled on 5 August 2014.
At the conclusion of the Games, Thoronka claimed, there were problems with getting flights back to Sierra Leone because of Ebola.
A sprinter from Sierra Leone who disappeared after the Commonwealth Games in Glasgow claims he has been living rough in London.