Socio-emotional functions seem well-preserved in the elderly. However, the long-lasting effects that the exposure to others’ distress may provoke in the brain remain unknown in this population. To evaluate how the aging brain reacts during and after emotionally challenging social events, we designed a new "task-rest" paradigm in which elderly participants (N=127) underwent functional magnetic resonance imaging (fMRI) while exposed to socio-emotional videos. We unveil neural markers of "emotional inertia" in brain activity and connectivity following negative scenes. Exposure to others' suffering induced differential activations that lingered over time into the subsequent resting-state in regions of the default mode network (DMN). Moreover, emotional elicitation potentiated subsequent resting-state connectivity between posterior DMN and amygdala, which in turn was related to anxiety, rumination, and negative thoughts. These findings uncover brain mechanisms underlying emotional resilience and empathy in the elderly and may help understand how poor social stress regulation promotes neurodegenerative diseases.