How do people with high trait self‐control achieve their success? This research aimed to investigate beliefs about emotion utility as a potential mechanism. Specifically, because beliefs about the utility of emotions predict emotion regulation and successful performance, we investigate the hypothesis that trait self‐control influences beliefs about the utility of emotions for self‐control. Two preregistered studies examined whether beliefs about the utility of emotions in everyday self‐control situations varied depending on the person (trait self‐control) and the situation (initiatory or inhibitory self‐control). Our key finding was that people considered positive emotions more useful for self‐control than negative emotions. This effect was also moderated by situational and individual factors, such that positive emotions were considered especially useful by participants with high trait self‐control and in situations requiring initiatory self‐control (with the opposite effect for negative emotions). This research suggests a potential role for instrumental emotion regulation in self‐control success.