Background: Fear of movement (kinesiophobia) after an acute cardiac hospitalization (ACH) is associated with reduced physical activity (PA) and non-adherence to cardiac rehabilitation (CR). Purpose: To investigate which factors are related to kinesiophobia after an ACH, and to investigate the support needs of patients in relation to PA and the uptake of CR. Methods: Patients were included 2-3 weeks after hospital discharge for ACH. The level of kinesiophobia was assessed with the Tampa Scale for Kinesiophobia (TSK-NL Heart). A score of > 28 points is defined as 'high levels of kinesiophobia' (HighKin) and ≤ 28 as 'low levels of kinesiophobia' (LowKin). Patients were invited to participate in a semi-structured interview with the fear avoidance model (FAM) as theoretical framework. Interviews continued until data-saturation was reached. All interviews were analyzed with an inductive content analysis. Results: Data-saturation was reached after 16 participants (median age 65) were included in this study after an ACH. HighKin were diagnosed in seven patients. HighKin were related to: (1) disrupted healthcare process, (2) negative beliefs and attitudes concerning PA. LowKin were related to: (1) understanding the necessity of PA, (2) experiencing social support. Patients formulated 'tailored information and support from a health care provider' as most important need after hospital discharge. Conclusion: This study adds to the knowledge of factors related to kinesiophobia and its influence on PA and the uptake of CR. These findings should be further validated in future studies and can be used to develop early interventions to prevent or treat kinesiophobia and stimulate the uptake of CR. Keywords: Acute cardiac hospitalization; Cardiac rehabilitation; Cardiovascular disease; Exercise; Fear of movement; Physical activity.