Charlie Brown's date of birth is up in the air: he was six years old in 1950 and six years old in 2000. (Although, according to waverider37
: "In one strip, Charlie Brown was actually 8 and a half... it was in a story where he left the baseball field, feeling a little woozy, and went to the hospital. During his stay Peppermint Patty confesses her love for him, and Lucy promises never to pull the football away. (Of course, she kept her promise... and Charlie Brown kicked her hand.) Remember that one?")
We do know that his father is a barber and that his grandfather was in the U. S. Army during World War II. His sister is Sally Brown. Contrary to popular belief, he is not bald: Schulz has stated that he is actually very blond.
He appears to live in Charles M. Schulz's home town of St. Paul, Minnesota, and goes to James Street Elementary School, as do most of the Peanuts characters. He is in Mrs. Donovan (not Miss Othmar)'s class... you know, with the speech impediment that makes her voice sound like a trombone.
He manages a baseball team and is their pitcher: line drives tend to disrobe him. His favorite baseball player is Joe Schlabotnik, although he also likes Sandy Koufax and Joe Garagiola.
During the summer, he always goes to camp. In fact, whenever he isn't in school, he seems to be at camp.
He is madly in love with The Little Red-Haired Girl, who doesn't even know he exists... but he's too wishy-washy to do anything about it.
In the comic strip, he has never kicked Lucy's football, has never gotten a kite into the air, and has never received a valentine on Valentine's Day—but he has done all of these things on television, so perhaps he should have considered a media change by now.
His dog is named Snoopy, but a thorough discussion of Snoopy is WAY beyond the scope of this node.