In a large pot over medium heat, add the oil and the Italian sausage. Sautee for 5-7 minutes or until the sausage is no longer pink.
Add in the onion and celery. Saute for an additional 3-5 minutes or until the onions become translucent.
Add in the garlic and saute 1 additional minute.
Add in the tortellini, chicken broth, fire-roasted tomatoes, and Italian seasoning. Add salt and pepper to taste. Bring to a boil, reduce to a simmer, and cook for about 5 minutes.
In the last minute of cooking, add the kale and stir it into the soup. It should soften and turn bright green.
Serve hot with parmesan cheese. Enjoy!