Bring a large pot of lightly salted water to a boil. Cook rigatoni in the boiling water, stirring occasionally until cooked through but firm to the bite, about 13 minutes. Drain.
Meanwhile, place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned, about 10 minutes. Remove bacon with a slotted spoon, leaving drippings in pan; set bacon aside.
Cook and stir garlic in the remaining bacon grease over medium heat. Add milk, cream cheese, and butter to skillet; stir until smooth. Stir Parmesan cheese, peas, ham, and bacon into cream cheese mixture; cook until peas are heated through, about 5 minutes more. Mix pasta into sauce to serve.
