Preheat the oven to 350 degrees F (175 degrees C). Lightly grease a 9×13-inch baking pan.
Bring a large pot of lightly salted water to a boil. Cook spaghetti in the boiling water, stirring occasionally, until tender yet firm to the bite, about 12 minutes.
Meanwhile, heat a skillet over medium-high heat. Cook and stir ground beef in the hot skillet until browned and crumbly, 5 to 7 minutes. Drain fat and stir in spaghetti sauce.
Drain spaghetti and place in a bowl. Add cream cheese, garlic, Italian seasoning, and garlic salt. Stir until cream cheese is melted and spaghetti is thoroughly coated. Spread a small amount of meat sauce in the bottom of the prepared baking pan; put spaghetti on top and top with remaining meat sauce. Sprinkle Parmesan and mozzarella cheeses on top.
Bake in the preheated oven until bubbly, about 30 minutes.
