Bring a large pot of lightly salted water to a boil. Cook elbow macaroni in the boiling water, stirring occasionally, until cooked through but firm to the bite, 8 minutes; drain.
Heat a large skillet over medium-high heat. Cook and stir ground beef and minced onion in the hot skillet until almost browned and crumbly, 5 to 7 minutes. Add garlic to ground beef mixture and cook until beef is browned, 2 to 3 more minutes; drain and discard excess grease.
Stir macaroni, tomato soup, corn, Italian seasoning, and seasoned salt into ground beef mixture; top with American cheese slices. Cover skillet until cheese is melted, 2 to 3 minutes; stir well.