Haq has been working as an investigative journalist in Libya, Syria, Afghanistan, Pakistan, Europe and other countries for 15 years, having gained his reputation as terrorism expert. In 2016, as an investigative journalist, he managed to uncover the conditions in refugee accommodation by using 35 different identities. Consequently, he published the book "Die Brutstätte des Terrors", for which he had spent several months "undercover" in over 30 different refugee camps in Germany, Austria and Switzerland. Simultaneously with his investigations into the refugee shelters, Ul-Haq began his undercover work in 150 European mosques on the issue of radicalization, resulting in his book „Eure Gesetze interessieren uns nicht“, published in October 2018 and represented at the Frankfurt Book Fair 2018.
As a terrorism expert, Ul-Haq and his colleague Susana Santina reported for ZDF from the Taliban's deradicalized camp in the Afghan-Pakistani border area (Peshawar). As a terrorism expert, he also reported for n-tv from Kabul on the question of how the Taliban are using the corona crisis for themselves. 
Ul-Haq's second reporting pillar is focused on the everyday problems of people in Asia. By risking his life, he reported on site during the takeover of Kabul by the Taliban in mid-August 2021, as a terrorism expert for well-known German- 
language media, including ORF, Kronen Zeitung, Welt-TV and Servus TV. Shams Ul-Haq was the first German journalist to conduct an interview with the Taliban leader and official Taliban spokesman Zabihullah Mujahid in Kabul.  
His journalistic career started 15 years ago with an interview with Benazir Bhutto. Since then, he has worked as a freelance journalist. He currently works or has worked for publishers such as the Sunday newspaper, Kleine Zeitung n-tv, ZDF and ARD, Die Welt, Wiener Zeitung, Tiroler Tageszeitung, FAZ, Huffington Post, among others.