The children's television landscape of the early twenty-first century found room for a particular strain of theatrical, physically committed performance — one that drew as much from stage tradition as from the conventions of the screen. Stefán Karl Stefánsson, born on July 10, 1975, in Hafnarfjörður, Iceland, brought exactly that sensibility to his work as an actor and singer.

Stefánsson trained at the Iceland University of the Arts and worked in both the Icelandic and English languages across his career. He is perhaps most closely associated with the children's television series LazyTown, in which he portrayed Robbie Rotten, the show's principal antagonist. The role demanded a heightened, pantomime-inflected style — elaborate costuming, exaggerated gesture, comedic villainy delivered with evident relish. That a performer working within the conventions of children's television could sustain such a character across the run of a series speaks to the range Stefánsson brought to his television work. His background as a singer informed that performance in ways that the role made visible, and LazyTown gave him a platform that reached audiences well beyond Iceland.

Stefánsson died on August 21, 2018, in Los Angeles, at the age of forty-three. In the years before his death, he had become a subject of considerable public attention beyond the immediate context of the series — LazyTown clips circulated widely online, and Robbie Rotten became a recognizable figure in internet culture. That renewed visibility, arriving late in his life, returned audiences to a performance he had built with care over the course of the show's production.