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 and rinse under cold water until chilled. Transfer macaroni to a large salad bowl.
Stir mayonnaise, vinegar, celery, tomato, green onions, Cheddar cheese, salt, and black pepper into macaroni until thoroughly combined. Cover and chill salad at least 2 hours.
Place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned, about 10 minutes. Drain the bacon slices on paper towels. Let bacon cool; crumble when cooled.