 Gaynor was born to a Jamaican father and an Afro-Brazilian mother.After leaving Samson (in which he played alongside Bruce Dickinson), Gaynor joined Simple Minds in 1982 as a session drummer for the "New Gold Dream" album (as a recommendation by record producer Pete Walsh), playing on six of the nine tracks.He later joined the band permanently for the "New Gold Dream" tour, as a replacement for Mike Ogletree.