He sports a pair of dress shoes, a black suit, a buttoned white-striped dress shirt, and loosened blue necktie accentuated by a beige trench coat. Although he has a very dire demeanor, his outward appearance radiates a natural calm and serenity which makes conversation easy and direct. Castiel is a strong, determined, impulsive, competitive and naïve celestial being. Like most angels, Castiel expresses little to no emotion, which creates flaws and complexities in his persona. Despite this, he does not display the blank apathy or mocking superiority that seem to characterize angels such as Uriel or Lucifer. His lack of emotion and understanding of human behavior such as sarcasm has led to several humorous situations throughout the show, and has occasionally gotten him into trouble with humans, ultimately leaving Dean or Sam to amend the situation. He does, however, become close friends with the brothers, who encourage him to be kinder, more caring and more selfless.

Sam has shaggy brown hair that grows longer and smoother in later seasons; he had a fringe as a child as well as in the first two seasons. Over the course of the show, he grew the fringe out. His eye color seems to change; sometimes they appear light green, sometimes they appear brown. Sam possesses a dual nature. He can be unusually kind, empathetic, intelligent and independent. But he can also be coldly pragmatic, cruel, vengeful, arrogant, and proud. Sam tends to be driven by feelings of anger and vengeance. It is only through constant, deliberate choice that Sam develops his better qualities and rejects his darker side.