Although Mårdøn Smet was educated to be a stone cutter, his career became comics. After working for some alternative magazines, he joined Rune Kidde, Peter Kielland-Brandt and others in founding the studios Tegneserieværkstedet, which was later renamed the Pinligt Selskab (Embarrassing Company). After making the pornographic 'Spildte Guds ord på Balle-Lars' ('God's Word Wasted on Lars'), he started to make the child-friendly 'Mumitroldene' ('The Moomin Trolls').
When his own style started to show in the series, the producers of the series didn't approve of his work anymore. Smet stopped making the series, but not before his 'Mumitroldene'-album 'Den lange vej hjem' ('The Long way home') was chosen best album of the year in 1995.
Starting in 1991, Mårdøn Smet also made the violent gag series 'Stig & Martha'. This bizarre cartoon couple has made several guest appearances in different Danish magazines. Smet has also drawn Disney comics for the publisher Egmont.