Cadet first became known for his association with Krept and Konan's Gipset crew in 2006, frequently appearing in music videos for the group's freestyles. Cadet released his first commercial mixtape, Are You Ready, on 4 April 2008. The Gipset crew garnered a considerable following across social media toward the end of 2010 through their freestyles about gang life and London living. Gipset broke up in 2013 after Krept and Konan signed their major label deal, and all other members focused on their solo careers.
Solo career (2015–2019)
Cadet began pursuing a solo career in 2015, and released his first freestyle, "Slut", via OSM Vision to YouTube in July 2015. The song was popular, and had received over 3.1 million views as of February 2019. The following month, Cadet was selected by Link Up TV to appear on their Behind Barz freestyle series, and his freestyle was uploaded to YouTube on 17 August 2015, receiving 2.3 million views as of February 2019. The freestyle attracted praise from American media outlet Complex, who called it "storytelling at its finest" and "better than some rappers' whole mixtape".
Cadet's debut EP, The Commitment, was released in 2016. The EP has features from Donae'o, Konan and Tis Rome. It was the first commercial release by the rapper. Cadet received considerable recognition after releasing "Letter to Krept" in 2016. In "Letter to Krept", Cadet reaches out to communicate with his cousin Krept about a misunderstanding between the pair. Cadet explains their story together, describing the principal events which lead to the distance between them at the point of this song’s release. Krept consequently released "Letter to Cadet" to share his side of the story. The single "Corn" featuring Big Tobz was released in December 2016.
On 29 August 2018, Cadet released the single "Advice" featuring Deno. It was his first charting single, having peaked at number 27 on the UK Top 40, and receiving over 18 million views on YouTube as of February 2019. The song was initially a freestyle which took place in Cadet's car before it was released as a single. His second charting single, "Pumpy", was released on 26 October 2018. The single was produced by Da Beatfreakz and had vocals from Swarmz and AJ & Deno. "Trendy" featuring Ay Em and Tion Wayne was released in December 2018. This would be the last single released during his lifetime.
Johnson was the cousin of fellow rapper Krept, and the two spent much of their childhood growing up together. Johnson converted to Islam at the age of 15 and mentioned his faith numerous times in his music.
Many of Johnson's contemporaries took to social media to pay tribute. Krept said he was "devastated and broken", and announced that a public tribute would take place the following day in Hyde Park, London. Deno released a tribute for Cadet titled "First Days" on 13 February 2019.