It is quite clear that the devolutionary settlement negotiated between the UK chancellor George Osborne and the leaders of the Greater Manchester Combined Authorities (GMCA) required local political actors to agree to oversight of the new arrangements by an elected metro mayor. In the intervening months since that announcement, governance arrangements for a Greater Manchester (GM) ‘metro mayor’ have proved to be both unique and fluid, drawing on earlier arrangements for electing mayors in Greater London, other city mayors, the Police and Crime Commissioner arrangements and the existing arrangements in the ten local authorities making up the GMCA. This article maps the development of the GM metro mayor and argues the unique governance arrangements set a path for other areas who want to extend a devolutionary agenda and negotiate enhanced devolutionary powers. However the governance arrangements developing for the GM metro mayor pose questions about the checks and balances built into these new executive arrangements. In particular how accountability and scrutiny of the metro mayor should be conducted going forward in GM, and elsewhere. In concluding it is argued that the metro mayoral model needs to include and prioritise democratic engagement alongside economic and social goals as a crucial element in making the new arrangements work.