Charlie Brown's traits and experiences are inspired by those of Schulz, his creator, who admitted in interviews that he'd often felt shy and withdrawn in his life. Both Charlie Brown's and Schulz's fathers were barbers and their mothers, housewives. Charlie Brown's friends, such as Linus and Shermy, were named after good friends of Schulz, and Peppermint Patty was inspired by Patricia Swanson, one of Schulz's cousins on his mother's side.

Source: Wikipedia