Background: Classroom engagement is key predictor of child academic success. Aim: The objective of the study was to examine how preschool cognitive control and the experience of family adversity predict developmental trajectories of classroom engagement through elementary school. Setting: Children were followed in the context of the Quebec Longitudinal Study of Child Development from birth to age 10.5 (N = 1589). Methods: Working memory was directly assessed when children were 3 years old and mothers reported child impulsivity, parenting characteristics, stress and social support when children were 4 years old. Elementary school teachers rated classroom engagement from kindergarten through Grade 4. Results: Growth mixture modelling identified three distinct trajectories of classroom engagement. Child working memory and impulsivity, and maternal hostility, social support and stress predicted greater odds of belonging to the low versus high engagement trajectory. Child impulsivity and maternal hostility and stress also distinguished between the low and moderate engagement trajectories. Conclusion: Our results suggest that targeting preschool cognitive control and buffering the effects of family adversity on children may facilitate academic success.