Preheat oven to 325 degrees F (165 degrees C). Place ham, cut-side down, into a roasting pan. Pin pineapple slices onto ham using toothpicks.
Mix pineapple juice and 1/2 cup brown sugar together in a saucepan; bring to a boil until glaze is slightly thickened, about 5 minutes. Remove saucepan from heat.
Bake ham in the preheated oven for 30 minutes. Pour glaze over ham and pineapple rings; continue baking for 30 minutes more. Sprinkle remaining 1 1/2 cups brown sugar over ham and pineapple rings; continue baking until ham is cooked through, about 30 minutes more. An instant-read thermometer inserted into the center should read at least 145 degrees F (63 degrees C).