Yaegashi was born in Daejeon, Empire of Japan on March 24, 1933, but raised in Hanamaki. After playing at Chuo University, he moved to Waseda University. After graduating from Waseda University, he joined Furukawa Electric in 1958. In 1963, he was selected "Japanese Footballer of the Year awards". In 1965, Furukawa Electric joined new league Japan Soccer League. He retired in 1969. He played 51 games and scored 14 goals in the league. He was also selected Best Eleven 3 times (1966, 1967 and 1968).