Workflow interruptions are one of the most commonly experienced stressors at work. This research expands existing literature on workflow interruptions in a diary field study. We apply a within-person approach and investigate detrimental effects of daily workflow interruptions on both daily satisfaction with performance and daily emotional exhaustion. Furthermore, we introduce polychronicity (the trait-like preference of a person to deal with several activities at the same time) as a buffering factor in this relationship. Results of the diary study with knowledge workers over 5 consecutive working days (N = 149, 644 daily observations) showed that on days on which participants experienced a large amount of workflow interruptions, they reported lower levels of satisfaction with their performance and higher levels of emotional exhaustion on that same day. Polychronicity failed to moderate the positive association between interruptions and emotional exhaustion. However, polychronicity significantly moderated the negative association between daily interruptions and daily satisfaction with participants’ own performance in a way that for people ranking high on polychronicity this negative association was dissolved.