Marketing researchers have devoted considerable attention to marketer-generated content (MGC), social media engagement behaviour (SMEB) and online relationships. Prior studies, however, do not integrate these critical elements of social media marketing. Our study, which is underpinned in the Elaboration-Likelihood Model, offers evidence that MGC leads to SMEB, which has a positive impact on relationship quality. A sequential explanatory mixed-methods study, which comprises a content analysis of the official Facebook pages of American political parties and semi-structured interviews with voters who engage with political MGC, reveals that peripheral cues are the primary drivers of SMEB. Based on the quantitative and qualitative evidence, we demonstrate that shares are a higher-involvement activity than likes. We recommend that political marketers should rely on distinct sets of MGC cues to elicit shares and likes.