Toshio Furukawa (original anime)
Shun was a famous athlete who specialized in high jumping. However, it's revealed that he used to be very weak and frail as a child.
In the episode Higher, Stronger! Cheers by Usagi, Shun was shown to have appeared on television quite a lot, as the track meets and competitions that he participated in were often televised. In one of the televised track meets, he sets a new Japanese record. Because of this, he was pretty popular and had a lot of fans, including Mimete and Hotaru. Mimete decided to make Shun her next target and went to the stadium where he trained so that she could steal his Pure Heart Crystal. Usagi, Chibiusa, Hotaru, Setsuna, Haruka, and Michiru went to the stadium as well so that Hotaru could deliver her fan latter to Shun in person. At the stadium, he saw Usagi and Hotaru being chased by a couple of bodyguards and went over to where Usagi and Hotaru were so that he could find out what all of the commotion was about. Usagi then persuaded Hotaru to give Shun the letter but Hotaru was unable to give it to him. Mimete then took this as a chance to steal Shun's Pure Heart Crystal and sent out U-Ndokai to chase off the bodyguards. After the Daimon chased the guards away, Mimete attempted to steal his Pure Heart Crystal. However, she was stopped by Sailor Moon and Sailor Chibi Moon. Mimete decided to and succeeded in distracting and once she was able to do so, she stole Shun's Pure Heart Crystal. After a battle, Shun got his Heart Crystal back. He decided to go talk to Hotaru, who came to after fainting during the battle. While he was talking to her, he told her that he sometimes wondered if his healthy self is just a dream. Hotaru then told him to do his best at the next meet and Shun tells her to do her best. At the end of the episode, it is shown that he had set another new record.
Respectively, the kanji in his family name means "already" or "now" (早) and the second character means "swift current" or "rapids" (瀬).
Strangely, if you type in "Hayase" and it's meaning in Japanese, it will come up as a Japanese girl name meaning "swift current" or "rapids", the meaning of the second character in his surname.
The character for "Shun" means "wink", "blink", or "flash" (瞬). But, if written in different kanji, it can mean "fast" or "talented", related to his running ability and how he was able to set a new record.