Using the self-determination theory (SDT) to create a need-supportive teaching environment to promote children’s learning, this study aimed to implement a need-supportive, structured fundamental motor skills (FMS)-based intervention during preschoolers’ 30-minute recess (2 lesson plans; 6 lessons/week for four weeks), and to examine intervention effects on preschoolers’ FMS and perceived competence. Twenty-four preschoolers (Mage = 4.80, SD = 0.32; 54% girls) were randomly assigned to intervention (N = 13) and control (N = 11) groups. Pre- and post-assessments measured actual FMS and perceived competence. A repeated measure MANOVA showed significant improvements between the groups over time in FMS and perceived competence (p < 0.05, Wilk’s Λ = 0.62, partial η2 = 0.38). A follow-up univariate test showed significant group × time differences in locomotor skills, ball skills, and total motor competence (p < 0.05). Cohen’s d results indicated medium to large effect size for the intervention group’s FMS and perceived competence, from pre and post intervention (ds 0.56–1.11). No significant improvements in FMS and perceived competence were observed in the control group. These findings indicate that the intervention can be used to enhance preschoolers’ FMS and perceived competence, which subsequently affect their physical activity and health status. (author abstract)