JJ Olatunji aka KSI

In 2008, when JJ was still in his early teens, he created his first YouTube account with the username “JideJunior”. On July 24, 2009, he opened his current YouTube account with the username KSIOlajideBT, where he posted gaming-commentary videos of the FIFA video game series from his bedroom in Watford, England. Once he started receiving a consistent monthly income from his uploads, he left his sixth-form college to focus on his YouTube career.

“Black Ops | One in the Chamber” is the oldest available video and JJ’s first video on this channel. He plays Call of Duty: Black Ops “One in the chamber” mode, where each player gets one bullet, a knife and three lives.

Polaris, a division of Maker Studios, signed JJ in October 2013. JJ has been a member of the British YouTube group known as the Sidemen since October 19, 2013. The group also sells only Sidemen merchandise and creates online videos that frequently feature challenges, sketches, and video game commentary.

After beginning to write and create comedy-rap songs for his YouTube channel in 2011, JJ collaborated with Dcypha Productions to release his debut single, “Lamborghini,” on March 23, 2015, which featured British grime MC P Money. On the UK Singles Chart, the song peaked at number thirty. “Creature”, which JJ independently released on June 23, 2017, peaked at position 100 on the UK Singles Chart.

To “take [his] music to the next level” and “further develop his music career in the US and internationally”, JJ signed a deal with RBC Records and BMG on November 4, 2019. It was confirmed that the label would be responsible for overseeing and reissuing JJ’s independent catalog recordings, in addition to managing the group’s upcoming releases. It was confirmed that day that JJ had already begun work on his debut studio album.

The alleged conflict between JJ and the British YouTuber Joe Weller started in 2018. They declared they would host an amateur boxing match on February 3, 2018, following Twitter arguments and diss tracks between the two. 1 minute and 37 seconds into the third round, JJ used a technical knockout to win the match.

It was revealed on February 24, 2018, that JJ and Logan Paul would square off in a white-collar boxing amateur fight. Two judges scored the fight evenly at 57-57, and a third judge scored it 58-57 in favor of JJ, resulting in a majority draw. On November 9, 2019, JJ and Paul had a rematch. Paul lost to JJ by a split decision, with two judges giving the fight to KSI (56-55 and 57-54, respectively), and one judge giving Paul (56-55) the victory.

He continued his professional boxing career by fighting businessman and professional boxer Joe Fournier, but this match ended in controversy and was later ruled a no contest. Most recently, KSI headlined a match against professional boxer Tommy Fury on October 14, 2023. The closely contested fight featured excessive clinching, which resulted in KSI's loss and the title via unanimous decision. The decision was initially reported as a majority decision due to an error in judge Rafael Ramos' scorecard.

On December 5, 2023, it was announced that KSI and IShowSpeed would fight in a charity sparring match, ending a year-long banter rivalry. Speed made a challenge to KSI on November 28, 2023, urging him to set up a date for the fight. The scheduled spar is scheduled for December 15th, 2023, with the proceeds benefiting the Anthony Walker Foundation. It's planned to be streamed simultaneously with the Jake Paul vs. Andre August fight, as an attempt to boycott the rival's fight.

As of 2023, JJ’s net worth is $35 million, according to Celebrity Net Worth. In 2018, Esquire magazine reported that, according to Social Blade, JJ can make up to £250,000 in advertising revenue from one video and that product endorsements on his social media cost around £75,000. JJ was listed as the director of three UK companies with equity of $2.2 million by Heavy that same year. JJ acknowledged that he also owns over ten properties “all around England” with a combined value of more than £10 million in an interview with Men’s Health.

KSI earns a massive portion from his YouTube channels, his music career, business ventures, boxing fights as well as from endorsements and brand sponsorships. The Sunday Times estimate that he earned about $15 million in 2020 and over $16 million the following year alone.

Olajide Olayinka Williams Olatunji was born on 19 June 1993. His mother, Yinka, is from Islington, London, and his father, Jide, is from Ibadan, Nigeria. He was educated at Berkhamsted School in Berkhamsted, where he met future partner and Sidemen member Simon Minter. He was raised in Watford, Hertfordshire. JJ is an Arsenal F.C. supporter. Deji, J.J.'s younger brother, is a YouTuber as well. The brothers were ranked first and second, by Tubular Labs in 2015 as “U.K.'s Most Influential YouTube Creators”.

JJ posts vlogs, reaction videos, challenges, and pranks on his YouTube channel. He posts a video every 3 to 5 days. His videos get more than a million views regularly, as well as an impressive number of likes.

Some of his most-watched videos are “Try not to laugh” challenges, Among Us let’s plays, videos with Logan Paul, reaction videos, meme videos, Reddit videos and videos where he plays horror games.

JJ reacts to a compilation of people getting into dangerous situations in this video.

JJ attempts the “Try Not to Laugh Challenge” in this video.

JJ watches a compilation of weird videos.

JJ reacts to KSI vs Logan Paul memes.

1. In 2015, JJ donated $10,000 to YouTuber Castro1021's online charity stream and took part in the Race Against Slime event to raise money for SpecialEffect, a foundation that develops technology to make video games more accessible for people with physical disabilities.
2. JJ revealed that he and Logan Paul had founded Prime, a hydration company, during an Instagram Live in 2022.
3. A video game called KSI Unleashed was released on iOS and Android devices in 2016 thanks to a collaboration between JJ and Endemol Shine Group.