Vladyslav Heraskevych wanted to compete in the Olympic skeleton event wearing a helmet adorned with images of Ukrainian war victims. As a result, he was disqualified by the International Olympic Committee.
Heraskevych appealed the decision to CAS, which rejected it.
"The lone arbitrator, who expressed full sympathy for Heraskevych's memorial gesture, is bound by the rules of the IOC's guidelines for athletes' expressions," CAS writes in a statement.
"These guidelines strike a reasonable balance between athletes' interest in expressing their opinions and athletes' interest in receiving undivided attention for their performances in the competitive arena."
Heraskevych used the helmet during his training sessions.
