Mindfulness-based interventions are increasingly recognized for their positive impact on children's physical, mental, emotional, and behavioral health. However, no mindfulness-based lifestyle interventions have focused on improving both the physical and mental well-being of economically marginalized preschoolers. Therefore, this one-group study aimed to examine feasibility, acceptability, and satisfaction of a 5-week mindfulness-based lifestyle intervention among preschoolers, caregivers, and childcare teachers. Caregiver-preschooler dyads were recruited from one urban and one rural Head Start childcare center. Outcome data were collected at baseline only, while evaluation data were obtained following the intervention. The intervention included three components: a school-based mindful eating and movement learning for preschoolers; a home-based caregiver training on mindful eating, movement, and parenting; and a school learning and home practice connection in mindfulness. Nineteen preschoolers, 18 caregivers, and three teachers participated. The enrollment rate was 40.4%. Attrition was 0% among preschoolers and 5.6% (n = 1) among caregivers (one caregiver passed away). Baseline data collection completion rate was 100%, with 88.9% (n = 16) caregivers and 84.2% (n = 16) preschoolers having valid ActiGraph data. Hair sample parental consent rate was 57.9% (n = 11), while sample collection rate was 90.9% (n = 10). Intervention implementation fidelity was excellent. Average intervention participation rates were 83.2% (n = 16), 72.2% (n = 13), and 55.6% (n = 10) for the preschooler component, caregiver meeting, and social media-based caregiver component, respectively. Acceptability and satisfaction with the intervention were high among caregivers and teachers. The results support the feasibility, acceptability of, and satisfaction with the 5-week intervention among preschoolers and caregivers from economically marginalized families and childcare teachers.