This study used a latent difference score growth model to investigate how changes in family structure (biological father and stepfather residence) and maternal employment are associated with American children's externalizing problem behaviors (EPB) from ages 4 to 10 and whether these associations vary by children's level of self-regulation. For all 4 year old children, living with a biological father at age 4 was associated with reductions in EPB at ages 4-6 and later years, with no variation by child self-regulation. Living with a stepfather at age 4 was associated with higher levels of EPB at age 4; however, for less-regulated children, stepfather residence at ages 4 and 8 was associated with reductions in EPB between ages 4-6 and from 8-10, respectively. Greater employment hours were associated with increased EPB in the next two years for less-regulated children of all ages; however, except for the age 4-6 transition, there was a lagged association that reduced behavior problems after two years and outweighed short-term increases.