Thomas Ruttig has a degree in Afghan Studies from Humboldt University, Berlin; he also studied at Kabul University, and speaks both Pashto and Dari fluently. Since 1983, he has spent more than ten years working in Afghanistan and Pakistan.

After his graduation in 1985, he joined the diplomatic service of the German Democratic Republic and served at its Kabul embassy in 1988-89. From 1989 to 2000, he worked as a foreign news editor in two Berlin-based newspapers and as a freelance journalist, concentrating on Afghanistan, Central Asia and developmental affairs, as well as the publishing of a developmental journal, the INKOTA Brief.

In 2000, he joined the UN mission (UNSMA) in Afghanistan and headed its Kabul office up to 9/11. He continued to work at the new mission (UNAMA) as a political affairs officer, was a member of the UN delegation at the Bonn conference on Afghanistan in 2001 and an advisor to the Afghan Independent Emergency Loya Jirga Commission in 2002. In 2002 and 2003, he successively headed UNAMA's Islamabad and Gardez offices. In 2003, he was appointed Deputy of the Special Representative of the European Union for Afghanistan and, in 2004, joined the German Embassy in Kabul as a political advisor. Between 2006 and 2008, he worked as a Visiting Fellow at the Berlin-based think tank SWP (Stiftung Wissenschaft und Politik/German Institute for International and Security Affairs) and, until 2009, as a freelance consultant and analyst.

In 2011, Thomas Ruttig was called by the Government of Afghanistan to join the Presidential Study Group on the Radicalization in Afghan Society. He has published extensively about Afghanistan and the region.