Buatsi was born on 14 March 1993 in Accra, Ghana. After his family moved to the UK, they resided in Croydon. Buatsi studied at Edenham High School. Buatsi graduated with a 2:1 degree in Management with Sports Science from St Mary’s University, Twickenham, while also competing as an amateur boxer.

At the 2016 European Boxing Olympic Qualification Tournament held in Samsun, Turkey, Buatsi defeated Ukraine’s Oleksandr Khyzhniak in his semi-final and Dutch boxer Peter Müllenberg in the final of the light-heavyweight tournament to secure his place in Rio as part of the Great Britain team.

At the 2016 Summer Olympics in the men’s light-heavyweight competition, he defeated Elshod Rasulov of Uzbekistan with a third-round knockout, to progress to the quarter finals.

Buatsi made his professional debut on 1 July 2017, when he fought Carlos Mena at The O2 Arena. Buatsi won the fight by knockout in the second round. He next fought on 1 September against Baptiste Castegnaro, winning by knockout in the fifth round. On 28 October 2017, on the undercard of Anthony Joshua vs. Carlos Takam at the Principality Stadium in Cardiff, Wales, Buatsi fought Saidou Sall in a six round bout, winning the bout 60-54.

On 23 March 2019, Buatsi defeated Liam Conroy via technical knockout in round three to claim the vacant British light-heavyweight title at the Copper Box Arena in London, England.