Hiroshi Masuoka took an active role in various rally activities for Mitsubishi Motors starting in 1982 and joined RALLIART INC. in 1990.
As a member of the Mitsubishi Motors works team "Team MITSUBISHI RALLIART", he competed in off-road events for many years. In 2002 and 2003, he became the first Japanese driver to win the Dakar Rally for 2 consecutive years.
One of Indonesia's top drivers, he has won the Indonesian Sprint Rally Championship in 1997, been an Indonesian Rally Championship winner three years in a row up to 2002, and more. In 2012, he was named brand ambassador for PT Mitsubishi Motors Krama Yudha Sales Indonesia (MMKSI). In 2019 and 2021, he won overall victories at the Indonesian Sprint Rally Championship in a Mitsubishi Xpander.
He has won numerous races since 2012, including the Thailand Super Series, Thailand Autocross Championship, and RAAT Thailand Endurance Championship International. In 2019, he took victories in the Thailand Super Series' Supercar GTC and other competitions.
With more than 30 years of racing experience, he has been crowned champion of the Mitsubishi Gymkhana Challenge Rallyart Cup ’89, won Round 1 of the Pennzoil Rally Championship ’91 in northern Thailand, and been a winner in many other categories. He is familiar with Mitsubishi vehicles, having driven a Mitsubishi Pajero in the 1996 Dakar Rally.