Preheat oven to 350F and grease a 9x13 casserole dish. Cook ziti in salted pasta water - cook 2 minutes less than package instructions.
Cut casing off of the sausage and cook and crumble in a skillet over medium heat until cooked through, about 5-7 minutes. Allow sausage to cool slightly.
Mix the marinara sauce, ricotta cheese, Italian seasoning and salt in the casserole dish. Mix in the cooked sausage and then the cooked and drained ziti pasta. Mix until everything is evenly combined. Top with the mozzarella cheese.
Cover with foil and bake in the oven at 350F for 30 minutes. Uncover and broil for just a couple minutes to brown the cheese.
Notes
You can store leftovers in the fridge for up to 4 days. You can freeze this dish for up to four months in an airtight container.