Surrogate decision-making support in the critical care field is a highly challenging form of support owing to its urgency and the fact that families are in crisis situations. Given this context, the diversification of families as a feature of modern society is thought to bring further difficulties to nurses who are involved in surrogate decision-making support. Therefore, this study sought to clarify the content of such support for diverse families that skilled nurses provided in the critical care field. We conducted semi-structured interviews with nine skilled nurses and a qualitative and inductive analysis of the obtained data. We extracted the following five categories of surrogate decision-making support. Even when there was no spare time in the critical care field, skilled nurses operated on the premise that family relationships and values are diverse while (1) “creating a foundation for surrogate decision-making that satisfied families” and (2) “making decisions based on a broad view of family relationships without being bound by preconceptions”, and they realized individualized support by (3) “adjusting the role of surrogate decision-makers based on family characteristics”. In cases where responses were difficult, it became clear that support was provided while (4) “responding to families in accordance with social norms” and demonstrating the ability to (5) “involve medical teams and finds solutions in difficult cases”.[[Please check that this conveys your intended meaning]]