Suicide is a leading cause of death worldwide, among the top 10 causes of death in every country, and one of the three leading causes of death for people aged 15 to 34 years. It has been increasingly recognized in recent years that people who attempt or commit suicide have a certain individual predisposition, part of which is given by personality traits, and in particular, impulsive-aggressive behaviors. This article reviews evidence suggesting that impulsive-aggressive traits are part of a developmental cascade that increases suicide risk among a subset of suicides. These personality traits, which do not appear to be a consequence of psychiatric disorder, seem to play a larger role among younger suicides and may mediate familial transmission of suicidal behavior. However, not all suicides are associated with impulsive-aggressive behaviors, and we need to better understand vulnerability to suicide among non-impulsive-aggressive suicide.