He won the inter-high school boxing tournament in his senior year in high school, and moved on to Nihon University, where he won amateur titles in two weight classes, compiling a distinguished amateur record of 117–8 (87RSC).

Uehara returned to the United States in August, 1974 to challenge WBA super featherweight champion Ben Villaflor, but lost by second-round knockout.

Uehara won the Japanese super featherweight title on July 21, 1971, knocking out his opponent in the first round.

Uehara was once again ranked as the number one WBA super featherweight challenger in 1980, and challenged Samuel Serrano for the Lineal and WBA super featherweight titles on the undercard of Thomas Hearns' win over José Cuevas in Detroit.

Uehara was losing on all three judges' scorecards before connecting with a right hook to knock out the defending champion in the sixth round.