KSIs real name is Olajide Olayinka Williams Olatunji. He was born on June 19, 1993, in Watford, Hertfordshire, England. KSI is an acronym that stands for Knowledge, Strength, and Integrity, which he got from his old Halo 3 clan group. He had to add the clans name "KSI" to his gaming name, "OlajideBT," so he could join the clan. However, as his popularity grew, the name "KSI" gained traction with his followers, and he embraced the name wholeheartedly.