Yokoyama was born in Nagasaki Prefecture on April 10, 1956.
After graduating from high school, he joined Japan Soccer League Division 1 club Nippon Steel in 1975.
He played 105 games and scored 29 goals in Division 1.
On August 23, 1979, Yokoyama debuted for Japan national team against North Korea.
This biographical article related to a Japanese association football forward is a stub.