According to a 1950 comic strip, his birthday is on October 30 but no strips from October 30 in subsequent years make reference to this. To himself, about Patty and Violet's gossiping): "I'll bet those girls are talking about me; I wonder what they're saying about me...gee...I was feeling so good too...now I'm all depressed...why does someone always have to spoil my day?!" Charlie Brown has a brief, yet surprisingly successful flirtation with a minor character called Peggy Jean whom he meets at summer camp. She kisses him and says she loves him. He is not always as successful with camp friends, including having a bunkmate who exclusively says to him, "Shut Up and Leave Me Alone".

For the main articles see Marcie and Charlie Brown's relationship and Peppermint Patty and Charlie Brown's relationshipSchroeder at times is usually the first to defend Charlie Brown. An example of this was when Violet offers Charlie Brown one of her leftover Valentine's Day cards on the day after the holiday. Schroeder thoroughly chastises her, however, Charlie Brown accepts the Valentine's card regardless, although he expresses appreciation for Schroeder's gesture.

However, this is contradicted by the July 17, 1955 Sunday strip, in which Charlie Brown tells Schroeder that he does not have yellow hair, as well as by the TV special You're a Good Sport, Charlie Brown, in which he says that he does not have much hair to cut. As another irony, Brown's father is a barber—just like Schulz's father. Rerun and Charlie Brown appear to have little interaction with each other in strips from the 1970s and 80s. The main exception being the storyline from 1973 in which Lucy convinces a reluctant Charlie Brown to allow infant Rerun to join Charlie Brown's baseball team. Rerun is instrumental in the team's win, as he is so small that the opposing pitcher cannot throw any strikes at him, and Rerun gets a game-winning walk. However, the victory is later voided because Rerun and Snoopy had bet five cents on the game. A song by The Coasters is called "Charlie Brown". Contrary to popular belief, this song is not an intentional reference to Peanuts.A character named Charlie Brown first appeared in Charles M. Schulz's Li'l Folks comic strip on May 30, 1948, more than two years before Peanuts started publication. Schulz used the name again for one of the three characters who appeared in the first Peanuts comic strip on October 2, 1950. Charlie Brown would go on to become one of the most well-known characters in Peanuts and is considered to be the main character in the strip. While all of the permanent characters (and a few minor characters) are his friends, he is often ostracized by them, and three of his friends even bully him, particularly Lucy van Pelt. Many of them (including the bullies), however, follow him as the manager of a baseball team, and that is where Charlie Brown's greatest skill, good leadership, is displayed. He leads the baseball team and keeps hoping for a victory despite their numerous failures and painful letdowns, yelling words of admirable encouragement to his players, leading them to the next game. Charlie Brown has many more traits, and his character is very deep. However, despite this, Charlie Brown is the only person to accept "Pig-Pen" for who he is, In one strip he even defended his uncleanliness "Don't think of it as dust. Just think of it as the dirt and dust of far-off lands blowing over here and settling on 'Pig-Pen!' It staggers the imagination! He may be carrying the soil that was trod upon by Solomon or Nebuchadnezzar or Genghis Khan!"