Ole Spiermann is active mainly with litigation and arbitration as well as public and international law.

In May 2009, Ole Spiermann finished his inquiry into financial matters between Greenlandic governmental bodies at the request the Greenland Home Rule.

In 2010, Ole Spiermann has been occupied with various litigations involving financial businesses, environmental protection and property of property as well as arbitration, not least disputes arising out of M&A transactions. He is advising the Danish Government before the International Court of Justice in proceedings relating to Kosovo.

Ole Spiermann is advising and representing Danish investors in disputes relating to the protection of their foreign investments. He has been advising self-government authorities, local authorities and private businesses on matters of public law pertaining, inter alia, to climate and energy and constitutional and administrative law.

Between 2005 and 2008, Ole Spiermann was the professor in international law at the University of Copenhagen, and he remains active as editor and contributor in Denmark and abroad.