In November 2007 Riekstiņš was elected the Minister of Foreign Affairs of Latvia and held this position until April 2010, when his party stepped out of the government.

In February, 2011 Ambassador Riekstiņš commenced his duties as the Permanent Representative of Latvia to NATO in Brussels.

He has led the delegation for the U.S.-Baltic Partnership Charter and also been the Head of Latvian delegation for Estonian-Latvian sea border delimitation (agreement concluded in 1997 and ratified), as well as Lithuanian-Latvian sea border delimitation (agreement concluded in 1999, not ratified yet).

Riekstiņš has a law degree from the University of Latvia, preceded by graduation of the Faculty of Pedagogy of the Latvian Academy of Sport Education.

In the run up to the 10th Saeima election in October 2010 Riekstiņš was a candidate for the parliament of the Political Alliance "For a Good Latvia", consisting of the People's Party and LPP/LC.