Cardiogenic shock represents a critical condition in which the heart is unable to maintain adequate circulation leading to insufficient tissue perfusion and end-organ failure. Temporary mechanical circulatory support offers the potential to stabilize patients, provide a bridge-to-recovery, provide a bridge-to-decision, or facilitate definitive heart replacement therapies. Although randomized controlled trials have been performed in infarct-related cardiogenic shock and refractory cardiac arrest, the optimal timing, appropriate patient selection, and optimal implementation of these devices remain complex and predominantly based on observational data and expert consensus, especially in non-ischaemic shock. This review explores the details of ‘when, how, and for whom’ temporary mechanical circulatory support devices should be used, examining specific clinical scenarios, the mechanisms by which they operate, and the patient populations that may benefit. The review also highlights the many gaps in evidence and need for better understanding of the interaction between human biology and these devices.