Preheat the oven to 375°F and lightly grease a loaf pan.
In a large bowl, combine the ground beef, panko breadcrumbs, egg, onion, garlic, 2 tablespoons brown sugar, 1/4 cup teriyaki sauce, and drained crushed pineapple. Mix until evenly combined but do not overwork the meat.
Transfer the mixture to the prepared loaf pan and shape into a firm loaf.
In a small bowl, stir together the remaining 3 tablespoons brown sugar, 1/4 cup teriyaki sauce, and pineapple juice until the sugar dissolves.
Pour the glaze evenly over the top of the meatloaf.
Bake for 50 to 55 minutes until the internal temperature reaches 160°F. Let the meatloaf rest for 10 minutes before slicing.