Purpose Playful work design (PWD) is a set of proactive strategies implementing fun and self-challenge at work to actively create better work conditions. Following the job demands-resources theory, this study aims to investigate the effects of PWD’s dimensions – i.e. “designing fun” and “designing competition” – on task and contextual performance (Study 1) and on the dimensions of organizational citizenship behaviors (OCBs) – i.e. altruism, conscientiousness and civic virtue (Study 2). Furthermore, the present research investigates the mediating role of work engagement (WE) for both studies. Design/methodology/approach Two samples of 339 and 141 Italian workers participated by filling in a self-report questionnaire. Measuring models and hypotheses have been tested by structural equation models. Findings Results suggest that WE partially mediates the relationship of the “designing competition” subdimension of PWD with task and contextual performance (Study 1) and with conscientiousness and civic virtue of OCBs, while “designing fun” shows a positive direct relationship only with altruism (Study 2). Originality/value This paper contributes to expanding knowledge about PWD’s effectiveness in facilitating performance and positive behaviors. Furthermore, it disentangles the different effects of PWD’s dimensions on performance. In light of the results, both employees and managers should be aware of the beneficial consequences of introducing fun and self-competitiveness when completing their own work activities.