Aim The purpose of this study was to investigate potential factors that influence nursing performance in South Korean intensive care units (ICUs). Background As nursing performance is directly related to patient outcomes in the ICU setting, identifying factors related to nursing performance at various levels could contribute to improving those outcomes. Method A cross-sectional descriptive design was employed with a convenience sample of 177 nurses having worked at least 6 months in an ICU. Data were collected from 2 to 16 March 2018. Results Workplace incivility from supervisors and patients and their families was negatively related to nursing performance, whereas a relation-oriented culture and task-oriented culture were positively related to nursing performance. The factors that predicted nursing performance were nurse age and a task-oriented culture. Conclusion Based on study findings, hospitals should focus on mitigating workplace incivility to help improve the nursing performance. Also, hospitals should develop strategies to assess organizational culture and foster relation- and task-oriented culture to maximize nursing performance.