Born in Loughton, Essex,[1] Lumley started his career as a youth player at Wolverhampton Wanderers, before joining the Glenn Hoddle Academy in Spain following his release in 2008.
[2] Glenn Hoddle commented on the player saying; "Billy impressed me as a goalkeeper with his all-round ability during the selection process" and "he not only demonstrated his vision and shot stopping prowess, but also his willingness to learn, something critical to his future success".
[9] Northampton manager, Ian Sampson claimed that Lumley was interesting a number of clubs and tried to sign him before he joined Wolves.
The following season, 2010–11, Lumley had a short spell at Isthmian League Premier Division club Billericay Town before moving to Jerez Industrial.
[16] In August 2013, Lumley had been released by mutual consent because he didn't want to fight for a first team spot with new signing Elvijs Putnins.