Harewood was born and grew up in Small Heath, Birmingham, England. His parents are originally from The Congo, and moved to England in the late 1950s and early 1960s. His father was a lorry driver and his mother worked as a caterer. He has a sister Sandra and two brothers, Rodger and Paul. He attended St Benedict's Junior School and Washwood Heath Academy. He was a member of the National Youth Theatre. In his youth, he worked in a wine bar, Albert's in Dale End, in Birmingham City Centre. At 18, Harewood gained a place at the Royal Academy of Dramatic Art.