She studied philosophy at Uppsala University, and started working as a journalist in the early 1960s.
She worked at Aftonbladet for 25 years and quit in 2002 after a conflict with the editor-in-chief Anders Gerdin regarding the content of a column about Princess Madeleine of Sweden.
The conflict started when Gerdin, without informing Kullenberg, modified the content of the column, downplaying the princess' problematic alcohol consumption.
[1] Moreover, Kullenberg served as a foreign correspondent stationed in Buenos Aires and Barcelona for six years.
[2] Kullenberg's first novel was Vänd på dig (published in 1967), and her second book, Överklassen i Sverige, was released in 1974, followed by Urp!