Oenoki was educated at and played for Shimizu Higashi High School. He won the national high school championship with his teammates including Kenta Hasegawa and Takumi Horiike. He continued his study and football at Waseda University. After graduating from the university in 1988, he joined Japan Soccer League side Yamaha Motors. When Japan's first-ever professional league J1 League started, Shimizu S-Pulse was founded in his local city. He joined the club in 1992 and re-united with his high school teammates Hasegawa and Horiike. He helped the club to win the 1996 J.League Cup, the second stage of the 1999 J1 League, and the 1999–2000 Asian Cup Winners' Cup. He made more than 250 league appearances for Shimizu and retired after the 2002 season.