Despite extensive research on parental involvement, gaps remained in understanding the quality of parental engagement and its longitudinal implications for various developmental outcomes. This study investigated the relationship between parental involvement and children's academic performance and overall development during the critical early years of education (K-2). Utilizing data from the Early Childhood Longitudinal Study, Kindergarten Class of 2010-2011 (ECLS-K: 2011), this study examined how parental involvement—as reflected in practices such as helping with homework, attending parent-teacher conferences, and fostering a positive learning environment—related to children's interest in learning, interpersonal skills, persistence, and performance in math and science. The participants included 18,526 children (average age of 5.70 years at the start), their parents, and teachers. The study design was longitudinal, tracking these participants from kindergarten through second grade. The findings revealed that while parental involvement generally declined as children progressed through early elementary school, positive relationships between PI and various developmental outcomes remained significant. Specifically, active parental engagement was associated with higher motivation, improved interpersonal skills, greater persistence, and enhanced performance in math and science assessments. The study highlighted the importance of fostering strong home-school partnerships and developing strategies to engage parents. These insights aimed to inform educational policies and practices that support children's holistic development, emphasizing the need for early interventions and ongoing parental involvement to ensure long-term academic success and personal growth.