Markus Gustafsson was 15 years old when he began his journalistic career at Skaraborgs Läns Allehanda in Skövde. He made a living as a reporter at Värnpliktsnytt and started working extra at Aftonbladet in parallel with university studies in Uppsala. In 1996, he returned to Värnpliktnytt as editor-in-chief and responsible publisher. In 1997–1998, he worked as deputy press secretary for Prime Minister Anna Lindh, then Minister of the Environment .
From 1999 to 2010, Gustafsson worked at Aftonbladet as deputy news director, news director and edition manager before being appointed editor-in-chief and head of the news department in 2010. In 2011, he quit as editor-in-chief at Aftonbladet for a project within Schibsted then described as “a Swedish equivalent to the Huffington Post”. In November 2013, the news app Omni was launched.