Background <p>Early childhood is a sensitive developmental period during which television exposure is widespread which may include portrayals of aggressive and prosocial behavior. Although prior research suggests modest associations between media content and child behavior, most studies focus on screen time rather than content quality and typically examine aggressive and prosocial content in isolation. From a public health perspective, there is limited longitudinal evidence on how early exposure to aggressive and prosocial television content, and their co-occurrence, relates to children’s social and behavioral development over time.</p> Methods <p>Data were drawn from the Growing Up in New Zealand longitudinal cohort. Children’s exposure to aggressive and prosocial television content at age 2 was assessed using fine-grained content coding of children’s most frequently watched television programmes. Children’s conduct problems, peer relationship problems, and prosocial behavior were assessed at ages 2, 4.5, and 8 using the Strengths and Difficulties Questionnaire (<i>N =</i> 5,338). A series of latent growth curve models were estimated to examine associations between aggressive content exposure, prosocial content exposure, their interaction, and overall television viewing time, with children’s initial levels and developmental trajectories of social and behavioral outcomes.</p> Results <p>Children’s television exposure frequently included both aggressive and prosocial behaviors, highlighting the heterogeneity of content viewed by young children. Higher exposure to aggressive television content was associated with higher levels of conduct and peer relationship problems at age 2, though these associations were attenuated after accounting for overall television viewing time, which predicted a steeper decline in conduct problems across childhood. Exposure to prosocial television content, the co-occurrence of aggressive and prosocial content, and all interaction terms with overall television viewing time were not associated with any outcome at age 2 or over time.</p> Conclusions <p>Overall, the findings suggest that early television content exposure is associated with behavioral differences early in development, though associations with developmental change across childhood did not contribute beyond the contribution of total television viewing time. From a public health perspective, these findings highlight the importance of considering television content quality alongside viewing quantity, recognizing that both are embedded within broader family and developmental contexts that warrant further investigation.</p>