Preheat the oven to 400 degrees F (200 degrees C).
Place potatoes, carrots, onions, garlic, sage, and basil in a large bowl; add oil and balsamic vinegar and toss to coat. Transfer to a rimmed baking sheet.
Roast in the preheated oven, tossing a couple of times for even cooking, until tender, about 30 minutes. Remove from the oven and sprinkle with brown sugar. Continue to roast for 10 minutes. Season with sea salt and pepper just prior to serving.