Designer Junichi Kawanishi was still coming to terms with his sudden fame on Thursday, a day after his design for the medals to be awarded at the Tokyo 2020 Olympics was unveiled to the world.

Kawanishi, a graphic designer from Osaka, won a nationwide competition to design the medals for the Olympics and Paralympics next year.

His design was unveiled on Wednesday during an extravagant ceremony in the Japanese capital with exactly one year to go until the Games, which starts on July 24.

The medals, which are 85 millimetres in diameter, feature the Greek goddess of victory Nike in their design along with the Olympic symbol and are made from recycled metals, collected from 6.21 million electronic devices donated across Japan.

Kawanishi said he wanted the circular design on the front of the medals to represent the globe and reflect light.

"By receiving light from various angles, I thought about the cheers from the public and those thoughts are reflected," Kawanishi told reporters on Thursday.

"Reflection of light reaches various directions so, I hope that the reflected light from the medal would reach all directions when it is worn by an athlete. That is my intention."

Kawanishi said he received a call last year which told him his proposal was selected from over 200 applications. He had to keep the medal design, and his identity, a secret until Wednesday.

"As many people applied, I thought there is no way I would be selected," he said.

"Experiencing the Olympic Games is a once in a lifetime experience. I was not born when they had the previous Games in 1964 so I was feeling happy already to experience a home Olympics.

"When I received a phone call, I was relaxing at home and had a few drinks. I became sober instantly but I remember that my heart was beating fast."