Alongside Shirin Ebadi, Dadkhah was one of the original co-founders of the Defenders of Human Rights Center, which was forcibly closed by Iranian authorities in December 2008.

In 2008, due to his activities as a human rights activist, Dadkhah was disqualified from standing for Iran's Central Board of the Bar Association.

Following the disputed June 2009 presidential elections and the ensuing crackdown on protesters, Dadkhah provided legal representations to hundreds of detainees.

[3] His clients would come to include Youcef Nadarkhani, the Iranian Christian pastor facing death for apostasy against Islam, as well as Ebrahim Yazdi, the former leader of the banned Freedom Movement of Iran.

His charges included being a member of an organization (the DHRC) seeking the "soft overthrow of the government" and "spreading propaganda against the system through interviews with foreign media.