Intensive care units are stressful environments and can bring negative psychological outcomes among critical care nurses. The aim of the present study is to describe critical care nurses’ characteristics and perceptions of health in relation to sex, and also provide their description of a healthy and sustainable work environment in intensive care units using a person-centred practice framework. A cross-sectional design was employed with 136 participants who responded to a questionnaire. Descriptive statistics and qualitative content analysis were used. Regardless of sex, critical care nurses perceived their current health to be significantly lower than their health before the COVID-19 pandemic. They described effective staff relationships and a supportive organization as being essential for a healthy and sustainable work environment. Critical care nurses have recovered to their perceived pre-pandemic health to some degree. Well-functioning teams and a supportive organizational system might nurture a healthy and sustainable work environment.