He played for St Michael's Senior High School and in Autumn of his junior year nailed down his spot as starting first baseman.

In his senior year, his school played in the Spring senbatsu tournament where Ishioka struck out twice in the first and only game leading to the team's exit.

[2] In his second year as third batter in the line-up, he helped the team to become runners-up and in 2014 he was selected to represent Japan at the 17th Asian Games[3] where he along with future team-mates Issei Endō, Masataka Iryo and Shun Ishikawa claimed the bronze medal.

In the lead up to Spring training he complained of lower back soreness and on 28 January Ishioka underwent surgery for an intervertebral disk hernia.

[7] He was selected alongside team-mates Takuma Kato, Shota Suzuki, Ryosuke Nomura, Hayato Mizowaki and Hiroki Kondoh to represent the Western League selection at the 2016 Asian Winter League held in Taiwan.