Len Darling was born in Gillingham. He played non-league football before joining his hometown club, Gillingham, of the Football League Third Division South, in 1933. After one season, during which he made 14 league appearances, he signed for Brighton and Hove Albion, where he established himself as a first-team regular. He made 141 league appearances in the pre-war period, served as an ARP ambulance driver during the conflict (as well as playing for Brighton and as a guest for Bournemouth & Boscombe Athletic i the wartime competitions), and played a further 58 league matches after the resumption. He also coached in schools and acted as trainer to the England Youth team. After football, he worked as a schoolteacher. Len died in Felixstowe, Suffolk in 1958 at the age of 47.