Add the olive oil to a large pot on the stovetop over medium heat.
Once the olive oil is hot, add the garlic and onion. Stir, cooking until the mixture is fragrant and the onions are translucent (3-5 minutes). Be sure not to overcook and brown the garlic and onions here, as they’ll continue to cook with the sausage!
Add the Italian sausage to the pot with the sauteed onions and garlic. Cook and crumble the sausage until fully cooked through and crispy.
Add the celery, carrots, tomato paste, diced tomatoes, sweet potatoes, kidney beans, and noodles to the pot. Then, pour in the broth.
Bring the soup to a simmer, then cook, stirring occasionally, for about 15 minutes.
After 15 minutes, add the green beans, lemon juice, salt, and pepper and stir to combine. Cook, stirring occasionally, for 3 minutes more, or until the green beans are tender and bright green.
Ladle the soup into bowls, garnish with parsley, and serve!