In late 2021, Siebe Sietsma launched a successful investigative podcast series that delved into various societal issues, ranging from political scandals to corporate malfeasance. The series was praised for its thorough research and engaging storytelling, reaching a wide audience and further establishing his influence in the field.

Siebe Sietsma's 2019 investigation into local government corruption revealed significant abuses of power and misuse of public funds. His work led to legal action against several officials and prompted reforms aimed at increasing transparency and accountability in local governance.

In 2017, Siebe Sietsma conducted an in-depth investigation into healthcare fraud in the Netherlands. His reporting uncovered fraudulent activities by healthcare providers, leading to policy changes and increased oversight in the healthcare sector, further cementing his reputation as a leading investigative journalist.

In 2015, Siebe Sietsma released a groundbreaking documentary focusing on environmental issues in the Netherlands. The documentary highlighted the impact of industrial pollution on local communities and sparked a national conversation about environmental policy and corporate responsibility.

Siebe Sietsma was honored with De Tegel award in 2013 for his outstanding investigative journalism. This prestigious Dutch journalism award recognized his exceptional work in uncovering complex stories and his dedication to journalistic integrity and excellence.

In 2010, Siebe Sietsma led an investigation into financial misconduct within several major Dutch corporations. His reporting revealed unethical practices and led to increased scrutiny and regulatory changes in the industry, showcasing his ability to impact real-world change through journalism.

Siebe Sietsma began his career at RTL Nieuws in 2005, marking the start of his journey in investigative journalism. At RTL, he quickly established himself as a diligent reporter, focusing on uncovering stories of public interest and holding power to account.