Adesanya was born in Lagos, Nigeria, the eldest of five children. His father, Oluwafemi, is an accountant and his mother, Taiwo, is a nurse. Adesanya attended Chrisland School, Opebi, and enrolled in its Taekwondo after-school club until he was removed by his mother due to an injury. In 1999, he relocated to Ghana with his family for 10 months, but due to his parents wanting their children to receive a well-recognised higher education, he settled in Rotorua, New Zealand, at age 10 and attended Rotorua Boys’ High School. Adesanya was not interested in sports during high school; but due to being bullied during his high school years and attributes the mistreatment he experienced to his decision to pursue martial arts later in life.
At the age of 18, he started training in kickboxing, after being inspired by the Muay Thai film, Ong-Bak. Two years later Adesanya made the decision to cease his studies in pursuit of a career in kickboxing and went on to amass an amateur record of 32–0 before turning professional and fighting in China. At the age of 21, Adesanya moved to Auckland, New Zealand, and began training in mixed martial arts under Eugene Bareman at City Kickboxing.
The rest is history, as he has competed and won several matches, making several records. His fighting skills and prowess has granted him recognition beyond the boxing rings. As much as Israel had his lows, he has always found a way to bounce back to his top form.
Recently, he won back his championship after getting defeated in previous matches.
Adesanya is multilingual. He is fluent in Yoruba, Nigerian Pidgin and English