At the 1972 Olympics in Sapporo he became the first Japanese athlete to win a gold medal and the second Japanese (after Chiharu Igaya) to win any medal at the Winter Olympics.

Previously he placed second at the 1970 World Championships and won the first three jumping events at the 1971/72 Four Hills Tournament.

[2] Kasaya was a long-term employee of the Nikka distillery, eventually becoming its section head.

[3] Kasaya died of heart failure in Sapporo on April 23, 2024, at the age of 80.

This biographical article relating to Japanese ski jumping is a stub.