Shareholder engagement has emerged as a central mechanism through which institutional investors seek to induce corporate sustainability improvements, yet existing research has largely conceptualized it as an organizational phenomenon, emphasizing coalition composition, ownership stakes, and firm-level receptivity. We argue that engagement is fundamentally an interpersonal process and examine how the characteristics of the individuals conducting dialogue (their relative seniority, issue expertise, and the stability and intensity of their communicative exchange) combine with institutional context to shape sustainability outcomes. Drawing on a unique dataset of bilateral engagements on environmental issues with 156 publicly listed companies across seven thematic campaigns (2018–2024), and using fuzzy-set Qualitative Comparative Analysis (fsQCA), we identify six distinct configurations associated with engagement success and three with failure. Our findings show that engagement effectiveness depends on how dyadic alignment, dialogue quality, and institutional context jointly configure. We contribute a microfoundational perspective to the engagement literature and introduce a “tailor-to-dyad” logic that extends prior configurational work.
