Garnet has a calm, focused, and stoic demeanor, and rarely speaks more than a few words at a time. She is the most in touch with the energy of the universe and uses this to summon her weapon. Though she's often the most stable member and a mentor to Steven, Garnet tends to act on intuition rather than seriously analyze a situation. For the most part, this works out well, but it has lead to some disastrous outcomes. She loses her usual stoic demeanor when she makes the poorly planned decision of fusing with Amethyst to form Sugilite in and creates an overly-exaggerated story while speaking to Connie's Mother over the phone.

While mostly level-headed, she occasionally demonstrates a fierce competitive spirit. As the defacto leader, Garnet is often the peacemaker of the Crystal Gems, especially when Pearl and Amethyst starting going at each other. She commands a large degree of respect from her team, but can be angered if not listened to or if an order from her has been disobeyed.