Add boiling water to jello and whisk until dissolved. Add 1/2 cup cold water to a measuring cup and add ice until water reaches 1 cup. Stir into jello until slightly thickened. Remove any unmelted ice.
Gently fold in whipped topping and stir in mixed berries. Refrigerate 30 minutes.
Spoon mixture into pie crust and refrigerate at least 4 hours or overnight.