Okayama was born in Sakai on April 24, 1978. After graduating from high school, he joined J1 League club Yokohama Marinos (later Yokohama F. Marinos) in 1997. On September 6, he debuted as forward and scored a goal against Sanfrecce Hiroshima. After the debut, he scored a goal for 3 matches in a row. However he could hardly play in the match from 1998. In June 1999, he moved to J2 League club Omiya Ardija. In 2000, he returned to Yokohama F. Marinos. He was converted to center back and played many matches. In 2001, he moved to Cerezo Osaka. He played many matches as forward. In 2002, he moved to J2 club Kawasaki Frontale and became a regular player as right defender of three backs defense. Although he played many matches in 2003, he could not play as starting member in most matches and he could hardly play in the match in 2004. In 2005, he moved to Avispa Fukuoka. He played many matches as mainly center back and the club was promoted to J1 end of 2005 season. However he moved to J2 club Kashiwa Reysol in 2006. He played many matches as center back and the club was promoted to J1 from 2007 season. However he could hardly play in the match in 2007 and he moved to J2 club Vegalta Sendai in August 2007. He played as regular center back in 2 seasons. After a half year blank, he moved to South Korean club Pohang Steelers in July 2009. He played for the club in 2 seasons and returned to Japan end of 2010 season. After a half year blank, he joined to Consadole Sapporo in June 2011. However he could hardly play in the match and left the club end of 2012 season. In August 2013, he joined Regional Leagues club Nara Club. The club was promoted to Japan Football League from 2015. He played for the club until 2017 season.