[2] From the age of 17, Demba attended The Half Moon youth theatre in Limehouse, before signing with an acting agency in Hoxton.

[10][11] In an interview with The National Student, Demba shared, "I’m hoping shows like this will open up the doors for more young black actors and this will be good for that reason alone.

"[12] In 2015, Demba was nominated for the Evening Standard 'Emerging Talent' Award for his performance in Patrick Marber's The Red Lion at the National Theatre, London.

[1][13] In 2020, Demba starred as Andy Okonkwo in the BBC drama Life, alongside Alison Steadman, Victoria Hamilton, and Adrian Lester.

[17] Demba has a leading role in the Netflix superhero television drama series, Supacell, released in June 2024.