Background: This study evaluated the utilization and outcomes of postcardiotomy mechanical circulatory support (MCS). Methods: This was a retrospective, single institution analysis of adult cardiac surgery cases that required de novo MCS following surgery from 2011-2018. Patients that were bridged with MCS to surgery were excluded. The primary outcomes were early operative mortality and longitudinal survival. Secondary outcomes included postoperative complications, and five-year all-cause readmission. Results: 533 patients required de novo postcardiotomy MCS, with the most commonly performed procedure being isolated coronary artery bypass grafting (29.8%). Median cardiopulmonary bypass and cross clamp times were 185 (IQR 123-260) minutes and 122 (IQR 81-179) minutes, respectively. A total of 442 (82.9%) of patients were supported with intra-aortic balloon pump counterpulsation, 23 (4.3%) with an Impella device, and 115 (21.6%) with extracorporeal membrane oxygenation. Three (0.6%) patients had an unplanned ventricular assist device placed. Operative mortality was 29.8%. Longitudinal survival was 56.1% and 43.0% at 1- and 5-years, respectively. Survival was lowest in those supported with ECMO and highest with those supported with an Impella (P<0.001). Freedom from readmission was 61.4% at 5-years. Postoperative ECMO was an independent predictor of mortality (HR 5.1, 95% CI 2.0-12.9, P<0.001), but none of the MCS types predicted long-term hospital readmission after risk adjustment. Conclusions: Postcardiotomy MCS is associated with high operative mortality. Even patients that survive to discharge have compromised longitudinal survival, with nearly only half surviving to 1-year. Close follow-up and early referral to advanced heart failure specialists may be prudent in improving these outcomes.