Former FIFA executive committee member Worawi Makudi is at the Court of Arbitration for Sport challenging his ban for forgery ahead of a Thailand soccer federation election.
Makudi said outside the court on Thursday he was "very confident. I didn't do anything wrong."
The former Thai federation president appealed against a 3 1/2-year ban by FIFA that expires in April 2020. He was also fined 10,000 Swiss francs ($10,100).
FIFA's ethics committee found him guilty of forgery, falsifying documents, and not cooperating with investigators. Makudi was alleged to have altered federation statutes before his 2013 re-election campaign.
He was convicted in a Bangkok criminal court, though said on Thursday that case was resolved in his favor.
"You know very clearly that the court in Thailand already decided I won the case, OK?" he said.
Makudi was a long-time ally of Qatar's Mohamed bin Hammam when sitting on FIFA's ruling committee for 18 years until 2015. He was voted out by Asian federations.