The increasing digitalization of work has intensified expectations of constant employee availability, extending job demands beyond formal working hours through work-related social media use. Drawing on the Job Demands–Resources (JD–R) model and Boundary Theory, this study examines the direct and indirect effects of off-hours work-related social media use on employee engagement and exhaustion, with work–family conflict as a mediating mechanism. Using a quantitative cross-sectional design, data were collected from 430 lecturers and professors in public and private universities in Rawalpindi–Islamabad, Pakistan. Structural equation modeling using SmartPLS shows that off-hours work-related social media use is positively associated with both engagement and exhaustion, reflecting its dual motivational and strain-inducing role. Furthermore, work–family conflict partially mediates these relationships by weakening engagement and intensifying exhaustion. The findings underscore the need for organizations to manage “always-on” digital expectations to safeguard employee well-being.