Recently, there has been a renewed academic interest in marketing practice. To capture the practical performance of marketing, however, a re-conceptualization of marketing practitioners is needed. To this end we explore how to characterize those who perform marketing. Working abductively by combining previous ideas on the constitution of economic agents with two longitudinal case studies of Swedish retail trade, we identify general dimensions of agential variation in three areas: in the constitution of agents, i.e. in how agents are put together/what agents are made of; in their programs of actions, i.e. the motives, interests and/or functions ascribed to agents; and in their capacities, i.e. in what market agents are capable of. We then trace implications of the observed heterogeneity of market practitioners for marketing.