The 80-year-old, who headed soccer's global governing body for 17 years until he resigned in June last year, was banned from all soccer-related activity last December along with the then European soccer boss, Michel Platini.
"My name wouldn’t be Sepp Blatter if I didn’t have faith, if I wasn’t optimistic," he told reporters as he arrived for the hearing. "I will accept the verdict because, in football, we learn to win, this is easy, but we also learn to lose, but this is not good, I wouldn’t want to lose."
The bans were imposed for ethics violations related to a payment of two million Swiss francs that FIFA made to Platini with Blatter's approval in 2011 for work done a decade earlier.
"I’m sure at the end...that the panel will understand that the payment made to Platini was really a debt that we (owed) him and this is a principle, if you have debts, you pay them," Blatter said.
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Platini also appeared for the closed-door hearing.
"I come, for the umpteenth time, to tell the truth," he told reporters.
Both men, who have denied wrongdoing, were initially banned for eight years, later reduced to six by FIFA's own appeals committee. Platini has already taken his case to CAS, who rejected his appeal but reduced his ban to four years.
CAS have not said when its final decision on Blatter's appeal will be announced.
Blatter resigned in the midst of a FIFA corruption crisis only four days into his fifth term.
Several dozen football officials, including former FIFA executive committee members, and entities were indicted in the United States on corruption-related charges last year.
Switzerland, for its part, opened a criminal investigation into the decision to award the 2018 and 2022 World Cups to Russia and Qatar respectively.
(Writing by Brian Homewood; editing by Mark Heinrich and Angus MacSwan)
