Preheat the oven to 400 degrees F (200 degrees C).
Heat a large skillet over medium-high heat. Cook and stir beef in the hot skillet until browned and crumbly, 5 to 7 minutes. Drain and discard grease. Stir in sauce, mushrooms, and olives. Cook and stir until heated through, about 2 minutes more. Transfer mixture to a 2-quart rectangular baking dish. Sprinkle mozzarella cheese on top of the casserole.
Flatten each biscuit with your hands and arrange on top of the cheese.
Bake in the preheated oven until biscuits are golden, 15 to 17 minutes.