"The panel concluded that the offences found to have been committed by Jerome Valcke were cumulatively of a serious degree of gravity and that, therefore, the sanctions of a ten-year ban and fine of CHF 100,000 were wholly proportionate," the court said in a statement.
Valcke, who served as top deputy to disgraced ex-FIFA boss Sepp Blatter, was initially banned in June 2016 and launched his appeal in February of last year.
Valcke and Blatter were key figures in the massive graft scandal that rocked FIFA in 2015 and forced sweeping changes within world football's governing body.
CAS said there was evidence supporting charges that Valcke breached FIFA's ethics rules "in the resale of FIFA World Cup tickets, in relation to his travel expenses, his involvement in a transaction between FIFA and a software development company, an offer of an improper benefit to the regional football union and his failure to cooperate with the FIFA investigation."
A French national, Valcke worked at FIFA from 2003 to January 2016, when he was sacked over his involvement in black market ticket sales and misconduct in television deals.
Subsequent investigations by FIFA's new management have also implicated Valcke in millions of dollars worth of unregulated spending, notably on private jets.
Separately, he has been implicated in a Swiss criminal investigation involving the possible illegal sale of World Cup media rights to beIN media, whose chairman Nasser al-Khelaifi is also the president of Paris Saint-Germain.