As of 2023, Jan Kleinnijenhuis continues his investigative work at Trouw, focusing on issues of national importance. His commitment to uncovering the truth and his ability to tackle complex subjects have solidified his reputation as a leading figure in Dutch journalism.

In 2022, Jan Kleinnijenhuis was honored with the De Loep award for his outstanding investigative journalism. This award recognized his persistent efforts in uncovering complex stories and his dedication to holding power to account through rigorous reporting.

During the COVID-19 pandemic, Jan Kleinnijenhuis focused on investigating the Dutch government's response to the crisis. His reporting highlighted the challenges and controversies surrounding the implementation of health measures, contributing to the national discourse on pandemic management.

In 2020, Jan Kleinnijenhuis published a comprehensive book detailing his investigative journey into the tax fraud scandal. The book provided an in-depth analysis of the systemic failures within the Dutch tax system and the impact of his findings on public policy.

Jan Kleinnijenhuis was awarded the prestigious De Tegel award in 2019 for his investigative work on the tax fraud scandal. This accolade is one of the highest honors in Dutch journalism, recognizing his exceptional contribution to uncovering critical issues in public administration.

In 2018, Jan Kleinnijenhuis played a pivotal role in uncovering a major tax fraud scandal involving the Dutch tax authorities. His investigative reporting brought to light systemic issues within the tax system, leading to national outrage and significant policy changes.

Jan Kleinnijenhuis began his career at Trouw, a major Dutch newspaper, where he quickly established himself as a diligent and insightful journalist. His work primarily focused on financial and political reporting, laying the foundation for his future investigative endeavors.