Olajide Olayinka Williams "JJ" Olatunji ( born 19 June 1993), known professionally as KSI, is a British influencer, musician, and former professional boxer. He is a co-founder and former member of YouTube group the Sidemen, the co-founder of Misfits Boxing and co-owner of several businesses, including Prime Hydration and Lunchly. KSI has also served as a judge on Britain's Got Talent since 2025.
Born in London to parents of Yoruba heritage and raised in Watford, KSI was privately educated at Berkhamsted School. He registered the YouTube channel KSIOlajidebt in 2009 and built a following through his commentary videos of the FIFA video game series. His content later diversified to include vlogs and comedic skits. In 2019, he was ranked second by The Sunday Times in its list of most influential online creators in the United Kingdom. In 2021, he was listed in the Europe Entertainment category of Forbes 30 Under 30; he was later ranked by Forbes as the second-top creator of 2023. As of April 2026, he has over 46 million subscribers and 16 billion video views across his four active YouTube channels.
Creating hip-hop music as early as 2011, he first achieved commercial success with "Lamborghini" (featuring P Money) in 2015. His debut EP, Keep Up (2016), topped the UK R&B Albums Chart. He released his debut studio album, Dissimulation, in 2020, which peaked at number two on the UK Albums Chart. His second studio album, All Over the Place (2021), debuted at number one and was certified platinum by the BPI; its lead singles "Don't Play" (with Anne-Marie and Digital Farm Animals) and "Holiday" both debuted at number two on the UK Singles Chart and were nominated for Song of the Year at the Brit Awards. He has achieved fourteen top 40 singles in the United Kingdom, with seven peaking in the top 10. He received the Brit Billion Award in 2024, for amassing over one billion music streams in the United Kingdom. He also starred in the direct-to-video comedy film Laid in America (2016), and has been the subject of multiple documentaries, including Amazon Prime Video's In Real Life (2023).
He was involved in a white-collar boxing match against Joe Weller in February 2018. Two further boxing events against American YouTuber Logan Paul took place, the second of which was a professional bout in which he won via split decision in November 2019. In August 2022, he fought two people in the same night, defeating rapper Swarmz and professional boxer Luis Alcaraz Pineda. In 2023, he fought FaZe Temperrr in January, Joe Fournier in May, and Tommy Fury in October, which he lost via unanimous decision.
Early life
Olajide Olayinka Williams Olatunji was born on 19 June 1993 in London and raised in Watford, Hertfordshire. His father, Olajide Olatunji, was born in Ibadan, Nigeria. His mother, Olayinka Olatunji (née Atinuke), is from Islington, London. He and his parents are from the Yoruba ethnic group. He was educated at Reddiford School in Pinner and Berkhamsted School in Berkhamsted, where he met future collaborator and Sidemen member Simon Minter.
KSI's younger brother, Deji Olatunji, is also a YouTuber and professional boxer who was previously known as ComedyShortsGamer. The brothers ranked first and second respectively as the "UK's Most Influential YouTube Creators" by Tubular Labs in 2015.
YouTube and online career
2008–2013: Beginnings and FIFA videos
KSI registered his first account on YouTube under the username "JideJunior" in 2008 while in his early teens. He registered his current YouTube account on 24 July 2009 under the name KSI Olajide BT, where he uploaded gaming–commentary videos of the FIFA video game series from his bedroom at his parents' house in Watford. "KSI" stands for Knowledge Strength Integrity, which was taken from a Halo clan.
He dropped out of sixth form college to pursue his YouTube career once he was earning steady monthly revenue from his uploads. In an interview in 2014, he recounted asking his teacher whether he should drop-out. His teacher asked how much KSI was making from YouTube, to which KSI answered, "around £1,500 a month", which was more than his teacher earned. His parents initially disapproved, but later became supportive and featured in a number of his videos. KSI later uploaded more vlog-style content and played a variety of games and in 2012, the channel reached a million subscribers.
KSI's rise to fame was not without controversy, with him being widely criticised for his self-described 'rape-face', a recurring joke on his channel during 2012 and 2013. He was the centre of a controversy following third-party allegations of sexual harassment of female staff at a Eurogamer event in 2012, that went so far as accusing him of sexual assaulting a spokesmodel Brandy Brewer, despite her tweeting that she consented to the motorboat, writing, "it's called comedy……relax". As a result, Microsoft cut ties with KSI and he was banned from Eurogamer events. KSI subsequently apologised "for any offence the video of 15 months ago may have caused in the short time it was on his YouTube channel, references to it since and subsequently used by other people" and stated his desire to move on from the incident and "be judged on the great content and value he gives to brands and partners, without controversy."
2013–2018: Joining the Sidemen
In October 2013, KSI signed with Maker Studios' sub-network, Polaris. Beginning 19 October 2013, KSI was part of the British YouTube group known as the Sidemen. The group produces online videos, most often consisting of challenges, sketches and video-game commentary, as well as selling exclusive Sidemen merchandise.
In July 2014, KSI and Comedy Central UK launched KSI: Demolished, a five-episode comedy roast web series in which British comedians such as Kojo, Michelle de Swarte, Bobby Mair, and Alex Lowe, take turns to roast KSI. In August 2014, KSI was the fourth most popular personality among U.S. teenagers, according to a survey done by Variety. On 18 August 2014, KSI teamed up with Endemol for a new sports show called Rule'm Sports. In October 2014, KSI signed with MLG.tv, a streaming media service focused on gaming and esports, as part of the roster of live streamers. In September 2015, KSI was ranked 15th on Business Insider's list of "The 15 most popular YouTubers in the world". A year later in November 2016, he was ranked first on Business Insider's list of "The 19 biggest British YouTube stars".
On 4 August 2017, KSI tweeted that he would be leaving the Sidemen, citing conflicts with fellow member, Ethan Payne. Shortly thereafter, he released a number of diss track videos criticising members of his then-former group, to which most of the members responded back with their own. Later that month, KSI released a video in which he claimed that he was being deported from the United States for receiving an incorrect visa. In November 2017, KSI released a video discussing whether his supposed falling out with the Sidemen was real or fake, saying, "[the drama] wasn't entirely real but wasn't entirely fake either."
2019–present: Career expansion, mainstream success, and leaving the Sidemen
In 2019, he was ranked second by The Sunday Times in its list of the top 100 UK influencers. In 2020, The Times named KSI to be Britain's biggest influencer. In April 2021, he was listed among Forbes 30 Under 30 Europe 2021 Entertainment list. In September 2023, Forbes ranked KSI as the second top creator of 2023, earning an estimated $24 million. In July 2024, KSI appeared in a YouTube video challenge by American YouTuber MrBeast titled "50 YouTubers Fight for $1,000,000".
On 31 May 2026, KSI announced that he would be departing the Sidemen as he became "too busy" for them, and that his last video with them would be that day. On 5 June, the Sidemen issued a joint statement confirming KSI's departure and wishing him the best. The group also stated that they had intended to release a coordinated farewell video, but KSI…