Okimune was born in Hiroshima Prefecture on September 7, 1959.
After graduating from high school, he joined Japan Soccer League Division 1 club Kawasaki Frontale in 1978.
In August 1979, Okimune was selected Japan U-20 national team for 1979 World Youth Championship.
On August 30, 1981, he debuted for Japan national team against Malaysia.
This biographical article related to a Japanese association football defender born in the 1950s is a stub.