In an interview for Interview Magazine David Ajala said "When I was in secondary school, my maths teacher said I had way too much energy and was too mischievous. He tried to convince me that if I did acting, I'd be popular amongst my peers".

Ajala trained at the Anna Scher Theatre and Courtyard Theatre drama school, then began his career performing with the Royal Shakespeare Company at in Stratford-upon-Avon where he performed in productions of “Hamlet,” and “A Midsummer Night's Dream,” among others. David has also worked at The Almeida Theatre, Donmar Warehouse and Royal court Theatre.

Ajala's Film credits include the independent feature STARRED UP alongside Jack O'Connell and Rupert Friend; the Wachowski feature JUPITER ASCENDING with Mila Kunis and Channing Tatum and FAST & FURIOUS 6 alongside the late Paul Walker and Vin Diesel.

Ajala was nominated “Best Acting Performance” by the Royal Television Society in 2009. On TV he has appeared in many TV shows with major roles in Black Box, Beowulf: Return to the Shieldlands, Nightflyers,, Falling Water and Supergirl. in addition, Ajala has also had major guest roles in award winning shows including “Law & Order: UK,” “Death in Paradise,” “Silent Witness,” and the wildly popular “Dr. Who.”

In October 2019, he joined the regular cast of season three of Star Trek: Discovery.