Objectives: To study (i) the association of general self-efficacy (GSE) on the course of subjective (i.e. basic and instrumental activities of daily living (ADLs and IADLs) and objective physical performance outcomes (short physical performance battery (SPPB)) among older persons from discharge up to 3 months post-discharge and (ii) the extent to whether motivational factors such as depressive symptoms, apathy and fatigue mediate this association. Methods: Prospective multi-centre cohort of acutely hospitalised patients aged ≥70 (Hospital-ADL study). Structural equation modelling was used to analyse the structural relationships. Results: The analytic sample included 236 acutely hospitalised patients. GSE had a significant total effect on the course of subjective and objective performance outcomes (ADLs: β = -0.21, P < 0.001, IADLs: β = -0.24, P < 0.001 and SPPB: β = 0.17, P < 0.001). However, when motivational factors as mediator were included into the same model, motivational factors (IADLs: β = 0.51, P < 0.001; SPPB: β = 0.49, P < 0.001) but not GSE remained significantly associated with IADLs (β = -0.06, P = 0.16) and SPPB (β = 0.002, P = 0.97). Motivational factors partially mediated the relationship between GSE and ADLs (β = -0.09, P = 0.04). The percentage of mediation was 55, 74 and 99% for ADLs, IADLs and SPPB, respectively. Conclusions: Motivational factors and GSE are both associated with subjective and objective performance outcomes. However, the relationship between GSE and subjective and objective performance outcomes was highly mediated by motivational factors. Taken together, this suggests that GSE is important to being physically active but not sufficient to becoming more physical active in acutely hospitalised older patients; motivation is important to improving both subjective and objective performance.