Cardiogenic shock (CS) complicating acute myocardial infarction (AMI) remains a leading cause of in-hospital mortality. While early use of the microaxial flow pump (mAFP) has been associated with improved survival in randomized trials of carefully selected ST-elevation myocardial infarction (STEMI) patients, its effectiveness in broader, real-world practice is uncertain. Using the National Inpatient Sample from 2016 to 2021, we conducted a retrospective observational cohort study of adult hospitalizations with AMI-CS undergoing percutaneous coronary intervention (PCI) on the first hospital day. Patients with missing demographic or outcome data, cardiac arrest, severe valvular disease, severe dementia, or left ventricular thrombus were excluded. Among an estimated 90,070 weighted hospitalizations, 15.5 % received mAFP within 24 h of admission. Compared with those who did not, patients treated with early mAFP were younger, more frequently male and White, and more often admitted to private for-profit hospitals. After multivariable adjustment for demographics, comorbidities, and prior interventions, early mAFP was associated with higher odds of in-hospital mortality (adjusted odds ratio [aOR] 2.31; 95 % CI, 2.09–2.54), invasive mechanical ventilation (aOR 1.51; 95 % CI, 1.38–1.65), major bleeding (aOR 2.52; 95 % CI, 2.27–2.80), and acute kidney injury requiring dialysis (aOR 2.58; 95 % CI, 2.11–3.16). Results were consistent across subgroups of STEMI-CS and NSTEMI-CS and when comparisons included other early forms of mechanical circulatory support. In this nationally representative analysis, early mAFP placement in AMI-CS was associated with worse outcomes, underscoring the importance of refined patient selection and highlighting the need for further research to define its optimal role in clinical practice.