The current randomized control trial evaluated the effectiveness of a new social-emotional learning (SEL) program, I Can Succeed for Preschools (ICS-PS). ICS-PS aims to improve preschoolers' social/interpersonal, emotional, and academic skills in an integrative way, focusing on children's core executive functions (EFs). The various components of the program are delivered sequentially throughout the school year via stories, physical activity, games, and role-playing. Six preschools were randomly assigned to either intervention (N = 49, mean age 66.37 months, 39% boys and 61% girls) or treatment as usual (TAU; N = 43, mean age 64.28 months, 56% boys and 44% girls). ICS-PS was delivered from November 2016 until May 2017. EF, emotional competence, social skills, behavior problems, and academic functioning were measured before and after the intervention. "Research Findings": Only children in the intervention group significantly improved in their EFs, receptive emotion knowledge, and emergent literacy, as well as in reducing internalizing problems. No change was found in social skills, indicating the need for more direct and explicit social skills training throughout the year. "Practice or Policy": These results, along with high treatment fidelity and program satisfaction, suggest that ICS-PS is a feasible and effective program for preschoolers. The research highlights the importance of prevention in early childhood.