Tatsuyoshi's father was a boxing fan and began training his son when he was a toddler. After graduating from middle school, Tatsuyoshi moved to Osaka to begin training, working part-time at restaurants to support himself. Tatsyoshi won the Japanese amateur bantamweight championship at age 17, becoming a candidate for the Seoul Olympics. Tatsuyoshi was featured in a local Kansai newspaper as one of Japan's best young boxers. His amateur record was 18–1–0.

Tatsuyoshi turned pro in 1989 and won the Japanese Bantamweight in his fourth professional fight. He won the WBC World Bantamweight Title in his eighth professional fight in 1991, the fastest of any Japanese boxer (Nobuo Nashiro tied this record in 2006, winning the WBA Super Flyweight Title in his eighth fight). However, he was discovered to have a torn retina while training for his first title defense, forcing him into rehabilitation.

Almost a full year after winning the title, Tatsuyoshi fought Victor Rabanales, who had become the WBC Interim Champion during Tatsuyoshi's inactivity. Tatsuyoshi lost by TKO in the ninth round but vowed revenge,^[1] claiming it was his twin brother "Joujirou" who had lost the fight. Tatsuyoshi fought Rabanales again on July 22, 1993, for the WBC World Bantamweight Interim Title, defeating Rabanales by 12-round decision. In September of the same year, he was found to have another eye injury; this time a detached left retina, forcing him to give up his interim title and nearly forcing him into retirement. Tatsuyoshi managed to continue his career, making a comeback in July 1994 in Hawaii, knocking out his opponent in three rounds. The WBC returned the interim title to Tatsuyoshi after the fight.

In December, 1994, Tatsuyoshi fought WBC Bantamweight Champion Yasuei Yakushiji. Being a title match between two Japanese fighters, the match generated huge media attention, and Tatsuyoshi was a huge favorite to win. However, he ended with a loss by 12-round decision, losing his interim title.

Tatsuyoshi challenged the WBC Super Bantamweight Champion twice in 1996 and 1997, but lost both times. Many began to believe he was no longer capable of fighting at the world level, and in November 1997, Tatsuyoshi challenged undefeated WBC Bantamweight Champion Sirimongkol Singwangcha, with the intent of retiring if he failed to win. Despite the odds, he won by TKO in seventh round, reclaiming his title after three years.

Tatsuyoshi recorded two title defenses before losing to Veeraphol Sahaprom on December 29, 1998. He challenged Sahaprom in August 1999, but lost again in the seventh round, and announced his retirement after the fight. He changed his mind shortly afterwards and resumed his training, making a comeback fight on December 15, 2002, winning by TKO after more than three years of inactivity. He won again in September 2003, but fell into inactivity again after injuring his left knee. There are no plans for a next fight, but he still trains with his son, Jukiya, who wishes to follow his father into professional boxing.

Tatsuyoshi admitted that he was bullied during his early childhood. He overcame it through boxing and never lost a street fight during his teens. He says he never used his fists when street fighting, because a bare knuckle punch could severely injure his opponent. He used open-handed slaps and elbows instead. Because of his experiences, Tatsuyoshi has appeared in public advertisements condemning bullying.

He is known to train exceptionally hard. Trainers used to keep their young boxers away from Tatsuyoshi, not because he might injure the younger boxers in a sparring session, but because the younger fighters might give up after seeing the enormous amount of time Tatsuyoshi spent training.

After losing an amateur bout, he left his gym for about half a year, homeless. He met his current wife at a cafe he stopped by during this period. Tatsuyoshi credits his wife for giving him the strength to return to his gym.

He is friends with comedian Hitoshi Matsumoto of Downtown and has appeared on his show Downtown DX. He is also friends with baseball star Ichiro Suzuki, who has attended several of Tatsuyoshi's fights.

He has appeared numerous times in the popular Japanese boxing manga Hajime no Ippo.

Tatsuyoshi turned 37 in May 2007. Tatsuyoshi had suffered several serious injuries, and his management has expressed a desire to not see him take further damage, making it difficult for him to fight in Japan. Tatsuyoshi "resurfaced" in Thailand in 2008 to continue his career abroad.^[2] When commentating on televised boxing matches, Tatsuyoshi has shown clear signs of being punch drunk (slurred speech and forgetfulness), worrying his fans.

• List of bantamweight boxing champions
• List of Japanese boxing world champions
• Boxing in Japan

• Boxing record for Joichiro Tatsuyoshi from BoxRec (registration required)