The main character is a Swedish teenager called Bert Ljung, living in Öreskoga, a fictional town in Sweden, in the late 1980s and early 1990s.
Bert starts as a 12-year-old child in the spring term of the 5th grade but later becomes a mischievous teenager discovering his own sexuality.
He married Märta Öberg, and they had two sons - Fredrik, and his younger brother Janne, who became a successful businessman in New York City.
He also plays soccer for the amateur team Öreskoga-Kamraternas Idrottsförening, before quitting in Bert och beundrarinnorna.
Torleif likes classical music, and plays the flute and the keyboards in the Heman Hunters.
Before his arrival from Sundsvall, rumors make everybody think he is the strong "Stor-Erik" or "Erik the Great" who is able to beat up Klimpen.
He has a fear of girls, after he showed his penis to his cousin at 5 years old and she told him it looked like a worm.
Rebecka Molin is the first girl Bert is in love with, which occurs in the mid 5th grade when the book series start.
Nadja Nilsson is a girl born in the autumn in Värmland, and lives with her mother in a cottage.
When her cousin Pavel visits Sweden in Berts vidare betraktelser, Bert is scared that secret US agents will spot them, and prevent him visiting his uncle Janne in New York City due to the poor relationship between the US and the USSR, as Czechoslovakia was a USSR-allied state.
Before, she has just been a name on a paper, and a schooldesk in the classroom, except when Bert says "–Sorry" to her in the 3rd grade for accidentally smashing a table tennis ball hitting her dental braces, knocking them out.