Background: Treatment with thoracic irradiation for classic Hodgkin lymphoma (CHL) leads to improved survival but also increases the risk of cardiovascular events. Left ventricular (LV) dysfunction is usually assessed by echocardiographic left ventricular ejection fraction (LVEF), whereas global longitudinal strain (GLS) can detect early subclinical LV dysfunction. The purpose of this study was to evaluate if conventional echocardiographic parameters and GLS are associated with cardiovascular events during long-term follow-up. Methods: 161 consecutive CHL patients treated with radiotherapy who underwent echocardiography > 10 years after diagnosis were assessed for eligibility. Multivariable cause-specific Cox regression was performed for a composite outcome of cardiac death and cardiovascular events and the competing outcome of noncardiac death. Results: 129 patients (61.2% female, N = 79) with a mean age of 46.3 ± 11.0 years at index visit were eligible for analysis. GLS was impaired in 51 patients (39.5%) and 10.9% had a LVEF of< 50%. The median E/e’ was 9.2 [7.2;12.7]. Adjusted for confounders, GLS > −16% showed a significant association with a near four-fold risk of the composite endpoint (HR = 3.95, 95% CI: 1.83–8.52, p < 0.001). LVEF < 50% (HR = 2.99, p = 0.016) and E/e’ (HR = 1.16, p < 0.001) also showed a significant relationship with the outcome. None of the aforementioned parameters were associated with the competing outcome. Conclusions: This study shows that LV dysfunction including impaired GLS in CHL survivors is associated with cardiovascular events and cardiac death.