<p>Regulatory problems in infancy are associated with internalizing and externalizing symptom trajectories across childhood, however, it is unknown whether early screen media exposure exacerbates this association. We studied 10,170 individuals from the Growing Up in Ireland ’08 cohort. Parents reported on their children’s regulatory problems at 9 months, screen media exposure at 3 years, and internalizing and externalizing symptoms at 3, 5, 7, and 9 years. Children were categorized based on their patterns of co-developing internalizing and externalizing symptoms. Subsequently, multinominal logistic regression analyses were conducted to estimate whether screen media exposure (&gt; 1&#xa0;h or &gt; 2&#xa0;h) moderated the association between regulatory problems in infancy and co-developing internalizing and externalizing symptom classes across childhood. There were four groups of children with distinct patterns of co-developing internalizing and externalizing symptoms. Presence of regulatory problems at 9 months and excessive screen media exposure at 3 years (particularly &gt; 2&#xa0;h) were independently associated with increased likelihood of all classes. Excessive screen media exposure at 3 years did not significantly moderate the association between regulatory problems at 9 months and internalizing and externalizing symptom trajectories.</p>