Cognitive functional therapy (CFT) has been shown to reduce pain and disability in people with chronic low back pain. The purpose of this study was to investigate participants' experience of CFT by comparing participants who reported differing levels of improvement after participation in CFT, potentially yielding insight into the implementation of this approach. This was a noninterventional, cross-sectional, qualitative study with an interpretive description framework. Individuals who had participated in CFT in 2 physical therapy settings (in Ireland and Australia) were recruited through purposive sampling based on disability outcomes postintervention (n=9), and theoretical sampling (n=5). This sampling strategy was used to capture a range of participant experiences but was not used to define the final qualitative groupings. Semistructured interviews were conducted 3 to 6 months postintervention. Three groups emerged from the qualitative analysis: large improvers, small improvers, and unchanged. Two themes encapsulating the key requirements in achieving a successful outcome through CFT were identified: (1) changing pain beliefs and (2) achieving independence. Changing pain beliefs to a more biopsychosocial perspective required a strong therapeutic alliance, development of body awareness, and the experience of control over pain. Independence was achieved by large improvers through newly cultivated problem-solving skills, self-efficacy, decreased fear of pain, and improved stress coping. Residual fear and poor stress coping meant that small improvers were easily distressed and lacked independence. Those who were unchanged continued to feel defined by their pain and retained a biomedical perspective. A successful outcome after CFT is dependent on instilling biopsychosocial pain beliefs and developing independence among participants. Small improvers may require ongoing support to maintain results. Further study is needed to elucidate the optimal approach for those who were unchanged.