Poor physical health places adults at greater risk for suicide ideation. However, the linkage between health and suicidal thoughts may emerge and become established during early adulthood, concomitant with other social processes underlying suicidality. Using nationally representative survey data from Waves III through V of the National Longitudinal Study of Adolescent to Adult Health (n = 8,331), we examine the emergence of health as a predictor of suicide ideation across the early adult life course (ages 18-43). We find that worsening health does not significantly predict suicide ideation until young adults approach the transition into midlife. Our findings suggest this may be due to the increasing severity of health problems, reduced social network engagement, and disruption of social responsibilities later in early adulthood. Our findings underscore the need for social science research to examine the relationship between mental and physical health from a life course perspective.