Place garlic in food processor and pulse until garlic is minced. Add garbanzo beans; puree until chickpeas have broken down into a paste. Pour in liquid from olives, 1 tablespoon at a time; puree until fully incorporated, about 2 to 3 tablespoons liquid in total.
Keep food processor running and slowly drizzle olive oil into hummus until smooth and desired consistency is reached. Add olives to the hummus and pulse 3 to 7 times until olives are chopped and evenly distributed.