BACKGROUND: Heart transplantation in the United States is increasingly performed amid expanding Medicare and Medicaid coverage. We analyzed the impact of recipient insurance trajectories on long-term graft and recipient survival following the 2018 United Network for Organ Sharing heart allocation change. METHODS: Adults aged 18 to 64 years undergoing first-time heart transplantation between October 2018 and March 2024 were identified from the national United Network for Organ Sharing solid-organ transplant registry. Recipients surviving ≥1 year were stratified by insurance trajectory across waitlisting, transplantation, and 1-year follow-up into 5 groups: continuous private, continuous public (Medicaid, Medicare, or Veterans Affairs), private-to-public transition, public-to-private transition, and multiple transitions. All-cause mortality and graft failure through 5 years posttransplant were assessed using Kaplan-Meier and multivariable Cox proportional hazards models with continuous private insurance as the referent. RESULTS: Among 15 864 recipients (mean age, 50.9±11.4 years; 31% female), 42.5% had continuous private insurance, 33.9% continuous public, 12.6% private-to-public, 4.8% public-to-private, and 6.3% multiple transitions. Five-year mortality was higher with continuous public insurance (15.1%) and multiple transitions (14.6%) than with continuous private (11.9%), and 5-year graft failure followed the same pattern (4.3% and 3.6% versus 3.2%). Continuous public insurance (hazard ratio [HR], 1.27 [95% CI, 1.15–1.40]) and multiple transitions (HR, 1.19 [95% CI, 1.12–1.43]) were independently associated with increased mortality. Continuous public insurance (HR, 1.29 [95% CI, 1.06–1.56]), private-to-public transition (HR, 1.32 [95% CI, 1.03–1.71]), and multiple transitions (HR, 1.09 [95% CI, 1.07–1.55]) elevated graft failure risk; public-to-private transition was associated with lowered risk (HR, 0.73 [95% CI, 0.45–0.92]). Residence in distressed communities was independently associated with increased mortality (HR, 1.21 [95% CI, 1.12–1.57]) and graft failure (HR, 1.31 [95% CI, 1.20–1.41]). CONCLUSIONS: Public insurance and insurance instability are associated with worse heart transplantation outcomes, while gaining private insurance was associated with improved outcomes, highlighting disparities in posttransplant care.