Heat the olive oil in a large skillet over medium-high heat.
Add the ground beef to the skillet and cook until browned, breaking it into crumbles as it cooks.
Stir in the diced yellow onion, green bell pepper, and minced garlic, sautéing for 3-4 minutes until the vegetables begin to soften.
Transfer the beef and vegetable mixture into the slow cooker.
Add the kidney beans, diced tomatoes, tomato paste, chili powder, ground cumin, smoked paprika, dried oregano, sea salt, and black pepper.
Stir all ingredients thoroughly to ensure the tomato paste and spices are evenly distributed.
Cover the slow cooker and cook on low for 6 to 8 hours or on high for 3 to 4 hours until the flavors are deeply melded.
Ladle the hot chili into a bowl and serve immediately.