gold medalist
Refers to a person who has won a gold medal, typically in sports or competitions.
彼はオリンピックの金メダリストだ。
He is an Olympic gold medalist.
Silver medalist, as opposed to gold.
Bronze medalist, as opposed to gold.
Compound of 金 (きん, 'gold') + メダリスト (medarisuto, from English 'medalist').