Although there is substantial support for the relationship between mentoring and work performance, empirical research has yet to fully explore the plausible positive psychological explanatory mechanisms of this relationship. This four‐year study examines the effects of mentoring on protégés' psychological capital (PsyCap; a higher‐order psychological resource that includes hope, efficacy, resilience, and optimism) and performance outcomes (formal performance appraisals) over time, in the context of an existing formal organizational mentoring program. PsyCap is examined as a mediator in the relationship between mentoring and performance. Utilizing 115 mentor‐protégé pairs, results support the effectiveness of the mentoring program in developing PsyCap and enhancing performance 1 year later in three cohorts of protégés, even after controlling for preprogram performance. Furthermore, PsyCap is supported as a full mediator between mentoring and performance. This is the first empirical study to explore this relationship, and one of the few mentoring studies to collect data over multiple time periods.

There is growing empirical support for the benefits of developing psychological capital (PsyCap), and the effectiveness of PsyCap interventions (PCIs) in the workplace. However, to-date, PCI delivery modes have not been compared. The first study in this article compares a face-to-face to an online PCI. The second study compares an online PCI to a micro-learning PCI utilizing a mobile application. Results from 228 participants assessed three times (before, immediately after, and six weeks after PCI completion) support the effectiveness and comparability of the three delivery modes, but also highlight notable advantages for online and micro-learning.