Based on the conservation of resources theory, this study investigates how and when supervisor bottom‐line mentality (i.e., one‐dimensional thinking that exclusively focuses on economic bottom‐line goals to the neglect of competing priorities) relates to employee creativity. We propose that supervisor bottom‐line mentality reduces employee psychological availability, resulting in decreased employee creativity. Additionally, psychological detachment, which allows employees to recover from job strain and to regain physical energy and psychological resources, serves as a buffer that weakens the indirect negative relationship between supervisor bottom‐line mentality and employee creativity through psychological availability. Empirical analyses using time‐lagged data from 540 employees of a hospital in eastern China (sample A) and 306 academic graduate students in Chinese universities (sample B) support all hypotheses. Theoretical and practical implications are discussed.