Add the olive oil, onion, and celery to a large soup pot. Sauté over medium-high heat for 5-7 minutes, until softened.
Stir in the garlic, followed by the beef. Cook until the beef has just browned, stirring occasionally (about 5 minutes). You shouldn't need to drain much fat if you're using lean ground beef, but feel free to drain some/most of it if desired.
Stir in the tomato paste, then add in the diced tomatoes, beef broth, potatoes, and Italian seasoning.
Increase the heat and bring the soup to a boil. Reduce the heat a bit so it's gently boiling. Cook for 20-25 minutes. You can cook it a little bit longer to intensify the flavor if you wish.
Season with salt & pepper as needed and serve immediately.
