Frequent changes of foster placement are known to have a detrimental effect on the long-term well-being of cared for children. Foster carers who take on children with challenging behaviours have to draw on resources, both internal and external, to help them build and maintain a relationship with the child that will last. Not all foster carers are successful in this regard. The aim of this qualitative study was to explore the role that the emotional resilience of foster carers plays in promoting placement stability. Seven foster carers, who had a track-record of stable placements (according to national criteria) with children exhibiting challenging behaviours, were recruited from a Local Authority in the North East of England. They attended a focus group and one-to-one interview. Verbatim transcripts were subjected to an inductive grounded theory analysis. Three potential underlying constructs, namely emotional resilience, interpersonal characteristics and external factors, were found to emerge from the data and identified as likely to influence foster placement outcomes. These data provide a springboard for further quantitative investigation with the potential to screen prospective carers to identify those best suited to ‘difficult’ placements in order to maximise success for the benefit of all concerned.