Heat olive oil in a large skillet over medium-high heat and sear the roast on all sides until browned, about 2-3 minutes per side.
Transfer roast to slow cooker and arrange onion, carrots, celery, and garlic around it.
In the same skillet, add tomato paste and cook for 1 minute, stirring constantly, then whisk in beef broth until smooth.
Pour the tomato mixture over the roast and add Italian seasoning, salt, pepper, and bay leaves.
Cover and cook on low for 8 hours or high for 5 hours until meat is tender and easily pulls apart.
Remove bay leaves, shred or slice the beef, and serve with the vegetables and sauce.