Background: Our current understanding of medical team competence is traditionally influenced by an individualistic perspective focusing on individual team members' knowledge, skills as well as on effective communication within the team. However, team dynamics may influence team performance more than previously anticipated. In particular, recent studies in other academic disciplines suggest that social ties between team members may impact team dynamics but this has not been explored for medical teams. We aimed to explore intensive care staff's perceptions about teamwork and performance in clinical emergencies focusing particularly on the teams' social ties. Methods: Semi-structured interviews were conducted with a purposive sample of intensive care staff. We used a thematic analysis approach to data interpretation. Results: Thematic saturation was achieved after three group interviews and eight individual interviews. Findings demonstrated that social ties influenced teamwork by affecting the teams' ability to co-construct knowledge, coordinate tasks, the need for hierarchy, the degree to which they relied on explicit or implicit communication, as well as their ability to promote adaptive behavior. Conclusions: Social ties may be an important factor to consider and acknowledge in the design of future team training, as well as for work planning and scheduling of team activities during clinical practice. More research is needed into the causal effect of social ties on team performance and outcome.