The persistence of negative emotions over time—referred to as emotional inertia—is a critical marker of maladaptive adjustment in organizational contexts, as it undermines recovery, flexibility, and well-being. Such negative emotions can also affect job applicants. Anxiety is an integral part of the job applicant experience, influencing both applicant reactions and interview performance (McCarthy et al., 2021). Moreover, with the "greying" of the workforce and applicant pools, it is important to examine the buffering effects of age on negative emotions. This study investigates whether regulatory emotional self-efficacy for negative emotions at work (RESE-W), defined as individuals' confidence in their ability to downregulate negative affective states, attenuates daily emotional inertia and whether this buffering function varies by age. A sample of 221 employees in socially demanding occupations participated in a 31-day daily diary study. Each evening, participants reported their levels of discrete negative emotions (e.g., sadness, anxiety, irritation) and job demands. Baseline assessments included RESE-W, neuroticism, and demographic characteristics. Results showed that RESE-W was associated with reduced carryover of negative emotions from one day to the next. Also, this moderating effect was age-dependent: younger employees benefited more strongly from RESE-W in mitigating inertia, whereas for older employees the effect was weaker and nonsignificant. These findings suggest that younger workers rely on perceived self-efficacy beliefs as compensatory resources, whereas older workers may draw upon regulatory strategies consolidated over the course of their lifespan. By elucidating age-related differences in the protective function of RESE-W, this study highlights the importance of tailoring workplace interventions to employees' developmental stages. In addition, the findings inform research on the applicant experience since selection and assessment contexts often elicit stress and negative emotions. Finally, recognizing how RESE-W varies by age can advance understanding of applicant adaptation and support the design of fairer, more inclusive selection processes.