We report on associations of retrospectively reported temporally prior mental disorders and Army career characteristics with subsequent first onset of suicidal behaviors in a large, representative sample of US Army soldiers who participated in the Consolidated All-Army Survey of the Army Study to Assess Risk and Resilience in Servicemembers (N = 29,982). Results reveal that among men and women, all self-reported lifetime disorders measured (some assessed with screening scales) are associated with subsequent onset of suicide ideation. Among men, three disorders characterized by agitation and impulsiveness (intermittent explosive disorder, panic disorder, and substance disorders) predict the transition from suicide ideation to attempt. For both men and women, being in the Regular Army (vs. National Guard or Army Reserve) predicts suicide attempts in the total sample. For men, a history of deployment and junior rank are predictors of suicide attempts after adjusting for preenlistment disorders but not accounting for pre- and postenlistment disorders, suggesting that postenlistment disorders account for some of the increased suicide risk among these career characteristics. Overall, these results highlight associations between mental disorders and suicidal behaviors, but underscore limitations predicting which people with ideation attempt suicide.