However the 23-year-old is fully aware he may be jeopardising his first team place in the Blades squad.
"I was getting pressure from them (Sheffield United) to stay but I sat down with the chairman (Kevin McCabe) and convinced him I wanted to go and it was a once in a lifetime (opportunity)," Carney told the Sheffield Star.
"I know I'll have a fight getting back in (to the first team) and the manager (Kevin Blackwell) told me so.
"But the Olympics is a one-off.
"I'm one of three over-age players and I'll never get another chance.
"Arnie (Graham Arnold) asked me early if I would make myself available and I gave him my word I'd be there."
Arnold plans to deploy Carney on the left-hand side of midfield in an attacking 4-3-3 formation at the Olympics.
"I am looking forward to an attacking role and I think it will suit me better," Carney said.
"I've come into the Olympic team to given them something (different).
"If we do beat Korea then we can go into the Olympics full of confidence."