He joined the Party"s Political Bureau in 1991 and served as Minister of Defense from 1991 to 2001. Subsequently he was Vice President from 2001 to 2006. He was elected as the LPRP"s General Secretary on 21 March 2006, in the aftermath of the Party"s 8th Congress, by the first plenum of the eighth Central Committee, succeeding Khamtai Siphandon as de facto leader of Laos.
He subsequently succeeded Siphandon as the 6th President of Laos on June 8, 2006.
In March 2011, he was reelected to his position as the LPRP"s General Secretary at the 9th LPRP Congress. In June 2011, he was re-elected as President of Laos at the seventh National Assembly.
He did not seek re-election to the LPRP Central Committee at the 10th LPRP Congress in January 2016, indicating his retirement. Bounnhang Vorachit was elected to succeed him as General Secretary on 22 January 2016.