Guy spent 35 years working in the finance sector in London before retiring in 2017. Prior to this, he trained as an accountant. He has been active in the voluntary sector, principally focussed on the provision of youth services. He was treasurer and then chair of a Hackney–based youth club for many years and is currently a trustee of London Youth. Guy was brought up in Kent and has lived in Sussex for 30 years. He is married with two grown-up sons.