ksi

On 2 February 2018, KSI released "Uncontrollable", featuring Big Zuu. The song played during KSI's ring walk for his boxing fight against Joe Weller and charted at number 89 on the UK Singles Chart. KSI released "On Point" on 17 August 2018, which was played during his ring walk for his second boxing bout.

On 12 April 2019, KSI released a collaborative album with Randolph titled New Age. It debuted at number 17 on the UK Albums Chart and at number one on the UK R&B Albums Chart.

2019–2020: New record label signing and Dissimulation
On 4 November 2019, it was announced that KSI had signed with RBC Records and BMG to "take music to the next level" and "further develop his music career in the US and internationally". In addition to managing KSI's future releases, it was confirmed that the label would be administering and reissuing KSI's independent catalogue recordings. That day, it was confirmed that KSI had already started recording his debut studio album. On 8 November 2019, "Down Like That", featuring Rick Ross, Lil Baby and S-X, was released as the album's lead single. It was performed live by the three featured artists as KSI's entrance music for his boxing rematch against Logan Paul. The song peaked at number 10 on the UK Singles Chart and it has been certified silver by the British Phonographic Industry (BPI) for sales of 200,000 units in the country. A further three singles preceded the album: "Wake Up Call", featuring Trippie Redd, which debuted at number 11 on the UK Singles Chart; "Poppin", featuring Lil Pump and Smokepurpp, which charted at number 43 in the UK; and "Houdini", featuring Swarmz and Tion Wayne, which debuted at number six on the UK Singles Chart and received a silver certification from the BPI.

KSI's debut studio album, titled Dissimulation, was released on 22 May 2020. The album debuted at number two on the UK Albums Chart and further charted in 15 other countries. It was the UK's best-selling debut album by a British artist in 2020 and it has been certified silver by the BPI for sales of 60,000 units in the country. The album spawned two further UK top 40 singles, "Cap", featuring Offset, and "Killa Killa", featuring Aiyana-Lee. KSI was scheduled to perform at Parklife, Longitude and Reading and Leeds music festivals in 2020 to promote Dissimulation, but these were later cancelled due to the COVID-19 pandemic.

KSI featured on "Lighter" by British DJ and record producer Nathan Dawe. The song peaked at number three on the UK Singles Chart and became one of the UK's best-selling songs of 2020. It has been certified platinum by the BPI for sales of 600,000 units in the UK and it was nominated for Best British Single at the 2021 BRIT Awards. KSI also featured on "Loose" by Zimbabwean-British artist S1mba, which peaked at number 14 on the UK Singles Chart.

2020–present: Second studio album and The Online Takeover
On 23 October 2020, KSI released the first single for his second studio album, "Really Love", featuring Craig David and Digital Farm Animals, which peaked at number three on the UK Singles Chart and has been certified silver by the BPI.

On 15 January 2021, KSI featured on "Don't Play" by Anne-Marie and Digital Farm Animals. The song debuted at number two on the UK Singles Chart, becoming KSI's highest-charting single in the UK to date, and was also certified silver by the BPI.

On 16 February 2021, KSI announced on Twitter the creation of his own record label named "The Online Takeover" in partnership with his music manager Mams Taylor. Shortly after, he announced the first signee of his label, which was American-British singer "Aiyana-Lee", who featured on the track "Killa Killa" on KSI's debut album "Dissimulation".

On 12 March 2021, KSI released the album's second single, "Patience", featuring YUNGBLUD and Polo G, which debuted at number 3 on the UK Singles Chart.