Harada was born in Osaka, Japan, and grew up within the Nara Prefecture region. He later moved to Tokyo, Japan. During his childhood, videogames were viewed with a great deal of suspicion in Japan. His parents would not buy him a home console, and as a result often sneaked into arcade centres, where he would occasionally be discovered and dragged out. He worked hard and ended up securing a place at Waseda University. He has studied judo, karate and a little bit of taekwondo in the past. He attended Waseda University along with Dead or Alive creator Tomonobu Itagaki and holds a degree in psychology. During his university studies, he took a few Chinese language courses, albeit finding it very difficult. After graduating from university, he joined Namco to become a promoter. His parents were initially unhappy with his pursuit in a career with the video game industry, but have since accepted him in his career.
During his first year working in the Namco arcade, Harada smashed the sales record two months in a row, and subsequently received an award of commendation from the president of Namco. Thanks to the award, Harada now had a platform to approach the management and request that they move him into game development. Towards the end of the first year at Namco, they gave him a position on the first Tekken title.
He voiced Forest Law in Tekken 3 and Tekken Tag Tournament, Marshall Law from Tekken until Tekken 5: Dark Resurrection, Yoshimitsu from Tekken until Tekken Tag Tournament and Kunimitsu in Tekken. Known for his sense of humor, such as comical friendship and rivalry with Street Fighter director, Yoshinori Ono, and jokes around about the character Leo in Tekken 6 because of the ambiguous gender. Harada is also a member of Project Soul (the team behind Namco's Soul franchise). He makes an appearance in Soulcalibur V as a Bonus Character in a Quick Battle challenge. He uses the Character Creation exclusive Devil Jin style from the Tekken franchise, the Mishima Style Fighting Karate. His BGM is called "Antares" which is also used in Tekken 5 stage Cathedral. In the game, he use his special outfit, the Heihachi Mishima's Tiger Gi. Harada maintains fairly active Twitter and Facebook accounts.