Newcomer proactive behaviors have positive, null, and sometimes contingent associations with adjustment outcomes. To further understand past mixed results, we draw on alternative theoretical perspectives to investigate how the newcomer relationship-building behavior of general socializing interacts with other relational resources to predict emotional and cognitive engagement. First, applying conservation of resources theory, we argue an augmentative effect under high insider guidance (via serial tactics). Second, utilizing attachment theory, we argue a compensatory effect under low insider guidance (via serial tactics). In Study 1 at a Chinese food manufacturer, unexpectedly, we found significant positive relationships between general socializing and engagement irrespective of serial tactics’ level. Drawing on the relational perspective of engagement, we propose structural factors provide a boundary condition, and therefore we extend our investigation to include task interdependence as a moderator. In Study 2 at an Australian university, the results support a compensatory effect of general socializing: When newcomers experience low serial tactics under low task interdependence, general socializing predicts higher emotional and cognitive engagement. However, when newcomers experience high serial tactics under low task interdependence, general socializing is detrimental for cognitive engagement. This supports a relational perspective combined with attachment-seeking in understanding resource combinations predicting newcomer engagement.