WASHINGTON — President Obama on Friday named James F. Dobbins, a veteran diplomat who oversaw the return of the United States to Afghanistan after the defeat of the Taliban in 2001, as his third special representative for Afghanistan and Pakistan, an administration official said on Friday.

Mr. Dobbins, 70, a former assistant secretary of state for European affairs with a history of difficult assignments from Kosovo to Somalia, will confront a fraught relationship between Washington and Islamabad, as well as a rapidly dwindling American military presence in Afghanistan.

The special representative post was first held by Richard C. Holbrooke, a larger-than-life diplomat who assembled an extensive staff at the State Department and threw himself into a broad range of political and development issues in Afghanistan.

After Mr. Holbrooke’s death in December 2010, the job went to Marc Grossman, another career diplomat who devoted his tenure to efforts, ultimately fruitless, to negotiate a political settlement with the Taliban. Mr. Grossman deliberately cultivated a lower profile than Mr. Holbrooke, scaling back his staff and negotiating behind closed doors.