European honorary consuls are members of a heterogeneous community of ‘volunteers’, outside the professional cadre of ministries of foreign affairs and diplomatic culture. This paper provides a critical portrait and reappraisal of the many faces of the HC in European diplomacy: simultaneously a public diplomat, a private citizen, a commercial agent, and a shadow diplomat. It reconstructs the institution of the honorary consul: its roles, functions, networks, and activities. It traces the HCs' European historical lineage and legal foundations, exploring the antecedents, ambiguities, and legacies that resonate through the institution’s messy evolution. We claim that the HC offers a means of understanding modern trends in European diplomatic practice. HCs straddle the division between public and private, extending the reach of the state while privatising its functions to a merchant corps for the efficient delivery of services to mostly foreign nationals. They are instruments of state authority and autonomous agents with competing interests. As public servants, they are facilitators and fixers, and as independent professionals, they network and may conduct covert state-led or private operations. We argue that debates on European diplomacy at a turning point should not overlook the significance of developments in the periphery of national diplomatic systems.