Lindgren may have borrowed the idea for the series from a similar story about Mr. O'Malley in the comic strip Barnaby (1942) by Crockett Johnson.

When Karlsson pushes a button on his stomach, it starts a clever little engine with a propeller on his back, allowing him to fly.

"Lillebror" has been changed to (Russian: Малыш, romanized: Malysh), which means "Junior" or "Little boy".

In 1971, the character was also adapted for the stage at the Moscow Satire Theatre, where Karlsson was portrayed by Spartak Mishulin.

A live-action version, Världens bästa Karlsson, was released in Sweden in 1974, as was an animated film in 2002.