Since the Angel never makes an actual appearance on the show, his existence must be accepted on faith.

Quinn is fairly certain her Guardian Angel is male, partly because when she talk to him about low-fat yogurt flavors, he seems very detached.

Among the deeds that Quinn attributes to her Guardian angel are: saving her life by pulling her out of the way of a falling light fixture, warning her not to get a sweater that Sandi had already bought, finding a lost earring, redirecting Mr. DeMartino's attention when she didn't know the answer to a question, preventing her from eating bad salad dressing, and allowing a pair of her jeans to be ruined so she could buy new ones.

Her angel seems to abandon her at Brittany's C-minus party where Quinn gets soda spilled on her and accidentally destroys Brittany's gift. Though she is devastated at first, she comes to understand that her Angel is only there for important things, like a sudden weight gain or a skin crisis.

Joey, Jeffy, and Jamie mistook Mr. O'Neill for Quinn's Guardian Angel, but it is safe to say that this was just another example of them being idiots.