Playful work design refers to the process through which employees proactively create conditions within work activities that foster enjoyment and challenge without changing the design of the job itself. Using flow theory, we propose that employees experience more work-related flow (work enjoyment, work absorption, and intrinsic work motivation) on the days when they playfully design their work – with positive implications for creative performance on these days. In addition, based on trait activation theory, we hypothesize that flow proneness strengthens the relationship of playful work design with work-related flow. A daily diary approach was employed to test the hypotheses. In total, 149 participants completed both baseline and daily questionnaires across five consecutive working days (total N = 552). Alternative Uses Task was used to measure objective creativity at work. Multilevel analysis showed that playful work design was positively associated with work-related flow, and work-related flow was significantly related to creativity – on a daily basis. In addition, employees high (vs. low) in flow proneness reported more flow and creativity when playfully designing their work. We discuss the theoretical and practical implications of these findings.@en