He has orange hair, sky blue eyes, a white shirt, a green bowtie, olive pants, and brown boots, and appears to be a little chubby. In the episode "Money Broom Wizard", he wore a yellow shirt, brown pants and brown shoes.
He tends to worry about things when they get bad like messes or when someone get hurt, as shown in Dinner Party where he's seen panicking after Clarence hurts himself from grabbing the insulation. He's also shown to be generally careful when doing things such as when he was performing a science experiment in "Honk". This behavior is likely the result of his family's meticulous and persnickety lifestyle and his parents' strict sense of discipline towards him. This is demonstrated when he constantly tells Clarence and the others to be careful or else his parents will kill him or when his mom is seen giving him a cold glare when Clarence asks about going to the attic, which wasn't allowed.
However, for as nervous and submissive as Breehn comes off as, he has been shown to have a rebellious side to his character. In the episode "Zoo", Breehn's peanut allergy forces the class to skip a lot of the exhibits in the zoo, which frustrates him. So later when the class has lunch, to show his mettle, Breehn voluntarily accepts a peanut butter sandwich from Percy (who didn't know that peanut butter is made from actual peanuts) and when Percy tells Ms. Baker he did this, he quickly eats and swallows it despite Ms. Baker telling him to spit out. It should be noted though that when his allergies kick in later and he ends up being taken away in an ambulance, he shows clear regret, saying that "It wasn't worth it.".
- Breehn is the only child in his family.
- The concept art for Breehn has an H in it, but in Clarence's Millions it was removed showing for the show his name is Breen.
- The name Breehn is actually a surname in reality.
- As shown in "Zoo", he is allergic to peanuts and peanut butter.