Declan McKenna was born in Enfield, Greater London on 24 December 1998 and grew up in Cheshunt, Hertfordshire where he attended St Mary's Church of England High School.
Declan McKenna sündis Enfield , Suur-London kohta 24. detsember 1998 ja kasvas üles Cheshunt , Hertfordshire , kus ta õppis St Mary kirik Inglismaa High School .