Adelayo Adedayo was born in London on 18 December 1988. She is of Yoruba Nigerian descent, and grew up in Dagenham.

She trained part-time at Identity School of Acting while studying law at Brunel University. Adedayo made her feature film debut in Sket (2011). On television, she became known for her roles in the BBC Three sitcom Some Girls (2012–2014)and the ITV2 series Timewasters (2017–2019). She plays a rookie police officer, co-starring with Martin Freeman, in the BBC One series The Responder, with the first series airing in 2022. In 2023 Adedayo was nominated for a British Academy Television Award for her performance in The Responder.