Military personnel commonly experience post-traumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI), both of which are associated with premature mortality. The present study examined two factors that may play a role in premature mortality—impulsivity and risk-taking behaviors—in a sample of 234 veterans screening positive for PTSD, mTBI, PTSD + mTBI, and controls. Analyses of variance demonstrated that veterans with PTSD, regardless of mTBI status, reported engaging in more frequent risky behaviors and reported a greater tendency to engage in impulsive behaviors when in a negative affective state. They also reported more premilitary delinquent behaviors and more suicide-related behaviors than controls. The present study highlights associations between impulsivity, risk-taking behaviors, and PTSD, and suggests continuity across the lifespan in terms of a predisposition to engage in impulsive and/or risky behaviors. Thorough evaluation of impulsivity and potentially risky behaviors is important in clinical settings to guide interventions and reduce the mortality and public health impact of high-risk behaviors in veterans.