Johannesson handily saw off the challenge of right wing rival Gudmundur Franklin Jonsson, who won just 7.8 percent of the vote. The turnout of the presidential election was 66.9 percent.
In the 2016 presidential election, Johannesson became the country's youngest-ever president after being chosen by 39.1 percent of the country's voters.
Prior to taking office, Johannesson taught history at the University of Iceland.