Cartoonist Jacques Moeraert, who uses the pseudonym Zak, was initially a bookkeeper, but switched to cartooning at the age of 25. Together with his friend Quirit, he published his first cartoons in Johan Anthierens' satirical magazine De Zwijger. He published the comic book 'Hoe kwamen onze jongens ertoe met de Romeinen te collaboreren?' (1983) and together with columnist Bert Verhoye, he drew 'De Vliegende Paap' (1985), a satirical comic book about pope John Paul II, published in the same year His Holiness visited Belgium. He was one of many cartoonists who drew a comic strip for Johan Anthierens' anti-royal book 'Brief aan een postzegel' in 1990.
When De Zwijger was disestablished in 1984, Johan Anthierens' brother Karel guided Zak to the left-wing newspaper De Morgen. In those early days De Morgen was often understaffed. In case an issue lacked enough photographs, Zak was called in to make some extra cartoons. Some editions had up to five or more drawings by Zak instead of the usual one or two. When the newspaper was on the brink of bankruptcy, he designed posters for benefit performances to help it out its financial troubles. Eventually it did establish itself on the Belgian newspaper market, with Zak as its house cartoonist.
His work also appears in De Tijd and the Dutch newspapers De Volkskrant, De Limburger and De Groene Amsterdammer. In France readers can enjoy him in Le Point.
Zak is best known for his ironic, tongue-in-cheek style. He always finds a way to joke about current topics, no matter how depressing they may be, and thereby reduces them to their right perspective. Earlier in his career, Zak often made jokes about specific politicians, but his cartoons later evolved to more timeless and less specific jokes about regular people. However: he still takes his inspiration from daily events. Since 1997 Zak publishes an annual pocket agenda, nicknamed 'Zakagenda', which compiles several of his best cartoons.
Zak has won the Royale Belge Prize for Best Press Cartoon (nowadays the Press Cartoon Belgium Prize) up to three times: in 1999, 2003 and 2015. His 2003 winning entry showed nuclear weapon inspectors in Iraq being saluted by soldiers who carry invisible weapons. This was a nod to the later proven fact that Iraqi dictator Saddam Hussein didn't have any weapons of mass destruction. In 2015 he won with a cartoon about the Syrian refugee crisis. The drawing showed a beach full of boat refugees, while a mother disappoints her child by saying: "We already went to see the boats come in, yesterday." Zak also received the Ark Prize for Free Speech (2000), the Inkspotprijs (2001), the BeNe Prize for Best Cartoon in the Dutch-language press (2003) and an honorary doctorate from the Brussels University in 2009.
On 2 September 2008, one of Zak's cartoons caused controversy in France. The drawing depicted coffins of dead soldiers with medals stuck to them. Two characters walk by and comment: "Even from Afghanistan the French come back home with medals", referring to both the death of 10 French soldiers during the Afghan War, as well as the Olympic Games. French senator Simon Loueckhote, who is related to one of the victims, asked President Sarkozy to register a complaint against De Morgen for publishing this cartoon.