Ueda began his Grand Prix career in extraordinary fashion, winning on his debut at the 1991 Japanese Grand Prix. That opening victory marked him immediately as a talent to watch in the ultra-competitive 125cc class, a category in which he would remain for the entirety of his professional career.
Ueda built steadily on his debut win through the early 1990s. By 1994, he had developed into a genuine title contender, ultimately finishing second in the 125cc world championship behind Kazuto Sakata. The runner-up position confirmed his status as one of the leading 125cc riders of his generation.
The 1997 championship produced another second-place finish for Ueda, this time behind a dominant Valentino Rossi in one of Rossi's early title campaigns. Ueda's consistency across the season placed him ahead of the rest of the field, though Rossi's form made the championship all but uncontestable.
In 1998, Ueda suffered a serious fall that broke his arm and caused nerve damage that threatened permanent paralysis of his right hand. Rather than retire, he worked with equipment manufacturer Spidi to develop what is believed to be the first motorised glove used in Grand Prix racing, a device that restored his ability to grip the throttle and brake lever sufficiently to continue competing at the highest level. His perseverance in returning to competition with such an adaptation became one of the more notable human-interest stories of late-1990s Grand Prix motorcycle racing.
Ueda continued racing in the 125cc class through the end of the 2002 season, adding to his win tally and remaining a points-scoring presence despite the lingering effects of his injuries. He announced his retirement at the conclusion of 2002, citing the cumulative physical toll of his career injuries and the need to allow his body to recover.
After retiring from competition, Ueda established Team Nobby, entering motorcycles in the All Japan Road Race Championship in the J-GP3 class. In moving from rider to team principal, he remained an active figure within Japanese domestic motorcycle racing.
Ueda's thirteen Grand Prix victories and two world championship runner-up finishes place him among the more accomplished 125cc riders of the 1990s. His determination to continue competing after a debilitating injury — and his role in developing a pioneering piece of adaptive racing equipment — added a further dimension to a career defined by resilience as much as raw speed.