Children (N = 90) from eight afterschool programs (n = 4 experimental sites with 47 children; n = 4 control sites with 43 children), along with the program leaders (N = 7) from the experimental sites, participated in a 12-week physical literacy intervention. Children were assessed on their physical literacy (movement competence, affect, confidence, and motivation) pre- and post-intervention using a suite of assessment tools that included the PLAYfun assessment of movement competence and a comprehensive child questionnaire. Experimental participants engaged in a daily physical literacy intervention at their afterschool program; controls engaged in their usual afterschool programming. Experimental group program leaders were assessed on their cognitions pre- and post-training and post-intervention, alongside questions regarding program acceptability and feasibility. Program leaders’ perceived knowledge and self-efficacy to implement the physical literacy program increased (p < 0.05) from pre- to post-training and these effects were maintained at post-intervention. No group differences were observed in the change of children’s motor competence, self-efficacy, or motivation from baseline to post-intervention. However, significant increases in affect were observed among participants in the experimental group (p < 0.05). Program leaders said they would recommend the program to future leaders. However, they reported challenges with implementation due to equipment availability and behavioral challenges. Results suggest a comprehensive physical literacy program during the afterschool period can be feasible to implement and can lead to improvements in the affective domain of children’s physical literacy. Further research on childhood physical literacy interventions is warranted.