Being extremely lazy, Robbie naturally opposes their attempts to spread a healthy influence to the people of LazyTown and employs various schemes, often involving the use of disguises, to discredit healthy living and run Sportacus (whom he refers to as "Sportaflop") out of LazyTown in every episode, although his plans are always foiled in the end.

He was based on his incarnation from the original musical and played by Stefán Karl Stefánsson on the children’s show.

In the second Icelandic stage play, the character was called Glanni Glæpur and, when he arrived at the town, he wore a completely black outfit; but, when he was disguised as Rikki Riki (a very wealthy man), he wore a purple coat, purple pants and shoes that are similar to those that Robbie wears in the television series—although at that point he did not yet have his hair covered in gel.

[3] In the television series, Robbie Rotten usually wears a two-piece suit of red and purple with gold pinstripes, formal shoes, a navy blue shirt with cuffs and cuff links, blue and red striped socks and black shoes with black soles.

[10][11][12] On August 21, 2018, his actor Stefán Karl Stefánsson died of bile duct cancer at the age of 43.