GMK is an acronym for "Grand Master King". In 2013, he launched his career on
SoundCloud, as a rapper, following the release of "Sounds Of The Future", featuring
Cruel Santino (credited as Ozzy B) & Yung from the music group L.O.S. On 24 April 2016, he released his extended play
Long Live the King, exclusively on
SoundCloud, with guest appearances from
Odunsi (The Engine), Genio Bambino, Bridge, BrisB, and
Cruel Santino. In a review for Pulse Nigeria, Abiola wrote "
Long Live The King is a pleasing story-telling work of art by ThatBoyGMK that would leave you wanting more". On 16 December 2016, he released "WasteMan", independently on
SoundCloud. The music video was released the same day, and directed by Falomo, in Lagos, Nigeria. On 9 February 2017,
The Native included the song in their Bumplist of 10 essentials you must-haves this week. On 21 March 2017, GMK released "Coconut lips", featuring Tomi Thomas. On 24 May 2017, he released "Pears & Mangos", and released "OTB", on 23 July 2017. In the same year, he opened for
Cruel Santino, and
Wavy the Creator, at The Lucid Lemons Curd 2 music and art showcase, held in Lagos, on August 5, 2017. He released "Lagbaja" featuring Odunsi (The Engine), on 20 November 2017. GMK was on
YNaija New Establishment class of 2019. The music video for Odunsi "Star Signs" was directed by The Candles, with cameo appearances from GMK. On 17 February 2021, following the partnership between
Warner Chappell Music, and
Love Renaissance, Monster Boys collective signed a publishing deal with Warner Chappell Music. ==Personal life==