From 1990 he was an advisor to Rupert Murdoch on investments in Poland.
Returning to Poland, in 1992 he briefly became deputy defence minister in the Jan Olszewski government. From 1998 to 2001 he served as deputy minister of foreign affairs in the Jerzy Buzek government. During the latter appointment, Sikorski became notorious in the Polish expatriate community, Polonia, for designing and promoting a particularly strict policy regarding Polonia’s citizenship status in Poland.  As a result of that policy, Poland refused to recognize the acquired citizenships of Polish emigrants, including hundreds of thousands of recent refugees from Communism and their children, and insisted that they be subject to all obligations of Polish citizenship, while at the same time making it impossible to renounce such citizenship because of an extremely cumbersome administrative procedure. This policy became known as the “passport trap” because it was mainly implemented as harassment of departing travellers (primarily citizens of the United States, Canada, and Australia) who were prevented from leaving Poland until they obtain a Polish passport.