Until recently, Seth was a specialist advising governments in Europe and Asia on public balance sheet management; financial efficiency strategies; financial infrastructure; and regional economic development. He led for Citi on public sector thought leadership and finance-related public policy. 

He was additionally part of Citi's internal Innovation Network. He served as a lead Secretariat member of HM Treasury's 2008-09 review of International Financial Services and the UK jointly chaired by the then Chancellor and Sir Win Bischoff. Seth has spoken widely overseas on this and other topics. Previous roles include covering Citi’s clients in the financial institutions sector; working on mergers & acquisitions in emerging markets; as well as a period in management consultancy. 

Seth additionally sits on the board of Wales in London, is a Fellow of the Royal Society of Arts, and is a member of the Welsh Government's advisory panel on Financial & Professional Services. Starting September 2012 he will be part of the first Master of Public Policy cohort in the new Blavatnik School of Government, Oxford University.

He holds an M.Phil. in International Relations from Trinity Hall, University of Cambridge, and a law degree where he specialised in European and International law. His focus during his Master's thesis was on Hong Kong as a commercial centre and how it interacted with China, and he has maintained a professional interest in Asia since.