(1) Background: Percutaneous left ventricle assist devices (pLVADs) demonstrated an improvement in mid-term clinical outcomes in selected patients with severely depressed left ventricular ejection fraction (LVEF) undergoing percutaneous coronary interventions. However, the prognostic impact of in-hospital LVEF recovery is unclear. Accordingly, the present sub-analysis aims to evaluate the impact of LVEF recovery in both cardiogenic shock (CS) and high-risk percutaneous coronary intervention (HR PCI) supported with pLVADs in the IMP-IT registry. (2) Methods: A total of 279 patients (116 patients in CS and 163 patients in HR PCI) treated with Impella 2.5 or CP in the IMP-IT registry were included in this analysis, after excluding those who died while in the hospital or with missing data on LVEF recovery. The primary study objective was a composite of all-cause death, rehospitalisation for heart failure, left ventricle assist device (LVAD) implantation, or heart transplantation (HT), overall referred to as the major adverse cardiac events (MACE) at 1 year. The study aimed to evaluate the impact of in-hospital LVEF recovery on the primary study objective in patients treated with Impella for HR PCI and CS, respectively. (3) Results: The mean in-hospital change in LVEF was 10 ± 1% (p< 0.001) in the CS cohort and 3 ± 7% (p< 0.001) in the HR PCI group, achieved by 44% and 40% of patients, respectively. In the CS group, patients with less than 10% in-hospital LVEF recovery experienced higher rates of MACE at 1 year of follow-up (FU) (51% vs. 21%, HR 3.8, CI 1.7–8.4,p< 0.01). After multivariate analysis, LVEF recovery was the main independent protective factor for MACE at FU (HR 0.23, CI 0.08–0.64,p= 0.02). In the HR PCI group, LVEF recovery (>3%) was not associated with lower MACE at multivariable analysis (HR 0.73, CI 0.31–1.72,p= 0.17). Conversely, the completeness of revascularisation was found to be a protective factor for MACE (HR 0.11, CI 0.02–0.62,p= 0.02) (4) Conclusions: Significant LVEF recovery was associated with improved outcomes in CS patients treated with PCI during mechanical circulatory support with Impella, whereas complete revascularisation showed a significant clinical relevance in HR PCI.