He began his Grand Prix career in 1993. From 1994 to 1996, Aoki competed in the World Superbike Championship, winning one race in that series. He returned to Grand Prix racing with Honda in 1997, enjoying his best season when he finished fifth in the 500cc world championship. A spinal injury in a 1998 motorcycle crash left him paralyzed below the waist. Takuma has continued to work with Honda, helping them develop cars for disabled people.
- Takuma's younger brother Haruchika in Ultraman Dyna is portrayed by Takuma's real life younger brother Haruchika Aoki.