Place the beef stew meat, sweet potato chunks, sliced carrots, diced onion, and minced garlic into the slow cooker.
Pour the beef broth over the ingredients and add the rosemary sprigs, salt, and black pepper.
Cover and cook on low for 7 to 8 hours until the beef is tender and the sweet potatoes are soft.
Remove the rosemary sprigs, then stir in the chopped kale during the final 30 minutes of cooking.
Stir once more before serving to distribute the kale evenly.