[2] Hirao started to play rugby since his first year at the secondary school days.
[6] He played for Mitsubishi Motors Kyoto and then, for Kobelco Steelers between 1999[7] and 2006.
[10] Hirao debuted for Japan in 1998, against South Korea in Bangkok, on 18 December.
He was also part of the 1999 Rugby World Cup squad, playing only the match against Wales.
[12][13] As of March 2008, he also was manager and coach of the Kobe club SCIX Rugby Club[14] and completed a master's degree in pedagogy and graduated in letters in Kobe Shinwa Women's University.