Background Implicit identification with death, measured by the Death–Suicide-Implicit Association Test (D/S-IAT), has been found to predict long-term suicide risk among adolescents. However, previous studies did not examine the predictive utility of D/S-IAT on short-term suicide risk trajectories among adolescents, especially during the critical period following discharge from the emergency room (ER) due to suicide behaviors. Objective This study examined the ability of the D/S-IAT to discriminate and predict suicide risk trajectories during the month following initial suicide risk assessment, among adolescents recently discharged from the ER. Methods One hundred and fifteen adolescents aged 9–18 years (77.4% female) were assessed at clinic intake. All participants completed D/S-IAT and self-report measures for suicide risk, depression, and anxiety during intake and 1-month follow-up. Results The D/S-IAT distinguished and predicted participants with continued heightened suicide risk at follow-up, above and beyond depression, anxiety, and suicide risk level at intake. Conclusions Along with conventional measures, D/S-IAT may be utilized to predict short-term suicide risk during post-ER discharge.