The electrocardiogram (ECG) is the most frequently performed cardiovascular diagnostic test, but it is unclear how much information resting ECGs contain about long term cardiovascular risk. Using a dataset of 312,422 resting 12-lead ECGs collected at [Medical Center 1, redacted for anonymity], we developed SEER, the preScient Estimator of Electrocardiogram Risk. SEER predicts five-year cardiovascular mortality with an area under the receiver operator characteristic curve (AUC) of 0.83 in a held-out test set at [Medical Center 1], and with AUCs of 0.79 and 0.83 when independently evaluated at [Medical Center 2] and [Medical Center 3] respectively. SEER predicts 5-year atheroscleroitc disease (ASCVD) with an AUC of 0.67 and is close in performance to the Pooled Cohort Equations for ASCVD Risk while being only modestly correlated. SEER has the potential to provide value by stratifying patients beyond current clinical practice.