Habits facilitate automatic behaviours and are resource efficient. Habits at work may be beneficial because they conserve cognitive‐attentional resources, thus fostering work engagement and goal progress. In a diary intervention study (2 daily assessments, 10 work days), we asked 72 employees to establish a new habit at work. Half of them additionally completed an intervention on the correct use of implementation intentions. All participants were given access to a follow‐up survey. In multi‐level analyses, automaticity of the new habitual behaviour predicted work engagement and goal progress at the day‐level. Implementation intentions predicted frequency of the habitual behaviour and in turn increased automaticity of this behaviour. The effects of implementation intentions were still evident at follow‐up. Contrary to expectations, the intervention did not increase participants' daily use of implementation intentions. The results indicate that implementation intentions might be used in everyday work to establish habits at work, thus increasing employees' efficiency and engagement.