Stefan Karl Stefansson was an Icelandic actor whose journey in the entertainment world truly began during his teenage years. Born on July 10, 1975, in Hafnarfjordur, Iceland, Stefan Karl Stefansson showed a passion for performance early on. He started studying acting at a young age, but eventually grew frustrated with what he saw as the overly strict and serious atmosphere of the Drama Academy of Iceland. Wanting more creative freedom, he jumped into the professional scene at just 19 years old—starting out as a puppeteer on television.

It wasn’t long before Stefan Karl Stefansson made his way into film and TV more formally. His big screen debut came in the 1994 comedy Aramotaskaup, followed by a small role in the short-lived series Baking Trouble (Channel 1, 1998). Over the years, he built up a solid resume with supporting roles across Icelandic cinema and stage productions. But everything changed when he crossed paths with gymnast Magnus Scheving.

Scheving had a vision: to inspire kids to get active through a fun, energetic show. That idea became LazyTown (Nickelodeon, 2004–2014), where Scheving played Sportacus, the athletic hero. For the villain, he turned to his friend Stefan Karl Stefansson, offering him the role of Robbie Rotten—a lazy, scheming character who despised exercise and loved lounging around. The concept took off instantly. After a successful musical special aired globally, Nickelodeon greenlit a full series and even helped build a dedicated studio in Iceland.

And just like that, Stefan Karl Stefansson became a household name. For ten years, he lived and breathed Robbie Rotten, turning the character into a beloved icon for children around the world. It was, without a doubt, the defining role of his career. Yet, tragically, it would also mark the final major chapter of his life.

In 2016, two years after LazyTown wrapped, Stefan Karl Stefansson received devastating news—he was diagnosed with cholangiocarcinoma, a rare and aggressive form of cancer. At the time, he was living in Los Angeles with his wife and their four children. Determined to fight, he returned to his homeland to undergo treatment. To help cover the mounting medical costs, Mark Valenti, the head writer of LazyTown, launched a GoFundMe campaign. The effort sparked an outpouring of global support, and unexpectedly, Robbie Rotten became a viral sensation. Fans and YouTubers created countless parodies of songs like “We Are Number One” and “The Mine Song,” turning Stefan Karl Stefansson’s character into an internet legend.

There was a hopeful moment in 2017 when surgery successfully removed cancerous growths. But by 2018, the disease returned—and this time, it was inoperable. After a month of chemotherapy, Stefan Karl Stefansson made the difficult decision to stop treatment. He quietly stepped away from public life, closing all his social media accounts to focus on peace and family.

On August 21, 2018, Stefan Karl Stefansson passed away at the age of 43. Just before his death, he was honored with the Order of the Falcon, one of Iceland’s highest civilian awards—a fitting tribute to a man who brought joy to so many. In accordance with his wishes, there was no formal funeral. As his wife shared, his ashes were scattered in secret, somewhere far out in the ocean—quietly returning him to the vast beauty of nature.