Although externalizing behavior typically peaks in toddlerhood and decreases by school entry, some children do not show this normative decline. A sample of 383 boys and girls was assessed at ages 2, 4, and 5 for externalizing behavior and at age 2 on measures of emotion regulation and inattention. A longitudinal latent profile analysis was performed and resulted in 4 longitudinal profiles of externalizing behavior for each gender. Poor emotion regulation and inattention were important predictors of membership in the chronic-clinical profile for girls, whereas socioeconomic status and inattention were important predictors of membership in the chronic-clinical profile for boys. Results are discussed with respect to the development of adaptive skills that lead to normative declines in externalizing behavior across childhood.