Gideon began AEC in 2015 after a successful early career in planning including a five year spell as a member of the senior civil service at the Planning Inspectorate. He is a chartered RIBA architect, MRTPI planner, and a qualified urban designer.

He is Council member of the National Infrastructure Planning Association, and is former UK Infrastructure Planning Commissioner, Planning Inspector, and Chief Executive of the Town & Country Planning Association, where he initiated a programme of EU projects on development and climate change, including on green and blue space adaptation. He was a member of the Ministerial Taskforce on Zero Carbon Homes, has been a Board Member of Swan Housing Group and is now a Partner at French Weir Affordable Homes.

Gideon was awarded an OBE for services to sustainable development in 2009.