With the rise of the gig economy, side hustles have become prevalent among employees. While employers remain concerned about stress and performance of multiple jobholders, research findings are mixed. Drawing on stress appraisal theory, we posit that multiple jobholders’ responses to stress in their full-time roles depend on their subjective interpretations of job demands, specifically challenge appraisals. Furthermore, we integrate the stress recovery framework to propose that side hustle experiences—characterized by mastery, control, relaxation, and psychological detachment—shape challenge appraisals and coping processes in full-time jobs. We also examine how the similarity between side hustle and full-time job moderates these relationships. We conducted two multi-wave studies to examine hypotheses. The results showed that mastery and relaxation experiences in side hustles facilitate challenge appraisal and proactive behavior in full-time jobs, whereas psychological detachment experience has the opposite effects; Control experience show no significant impact. Additionally, Study 2 reveals that similarities between side hustles and full-time jobs strengthens the positive indirect relationship between mastery experience and proactive behavior via challenge appraisal. This research contributes to multiple jobholder research by adopting stress recovery and appraisal perspective, offering new insights into how side hustles influence stress and proactive behaviors in full-time jobs.
