Occurrence and recurrences of suicidal ideation (SI) were modeled among boys/men assessed annually from ages 12 to 29 years. Multiple-spell discrete-time event history analyses permitted (a) determination of whether risk for SI escalates with prior experiences (Spell effects), (b) while accounting for changes in risk with time (Period effects), and (c) controlling for vulnerability factors. Arrest records and self-reported SI (presence/absence in past week), depressive symptoms, alcohol/substance use, and antisocial behavior were collected annually from 205 boys recruited on the basis of community risk for delinquency. Parents’ self-reported psychopathology and SES were collected in childhood. Period effects supported decreasing risk over time. Spell and time-varying, one-year lagged substance use and depressive symptoms independently predicted increased risk for SI. Models involving SI with intent were explored. Consistent with Joiner’s theory, with key propensities controlled, risk for young men’s SI increases with past experience of SI; yet, risk also decays over time. Targeting conditions that confer risk for SI is essential. Preventing and delaying SI occurrence and recurrence may represent additional, independent mechanisms by which prevention efforts operate.