Denis Sassou Nguesso (born 23 November 1943) is a Congolese politician who has been the President of the Republic of the Congo since 1997; he was previously President from 1979 to 1992.
Under pressure from international sources, he introduced multiparty politics in 1990 and was then stripped of executive powers by the 1991 National Conference, remaining in office as a ceremonial head of state.
He stood as a candidate in the 1992 presidential election but was defeated, placing third.
Sassou Nguesso was an opposition leader for five years before returning to power during the Second Civil War (1997–1999), in which his rebel forces ousted President Pascal Lissouba.
Following a transitional period, he won the 2002 presidential election, which involved low opposition participation; he was re-elected in the 2009 presidential election.
The introduction of a new constitution, passed by referendum in 2015, enabled Sassou Nguesso to stand for another term.
He was re-elected in the 2016 presidential election with a majority in the first round.
Sassou Nguesso is backed by a variety of political parties, most importantly the PCT.