Sanders was born in New York, and educated at Brooklyn College and the University of Chicago. He settled in Vermont in 1964. He was a member of and a candidate for the Liberty Union Party in the 1970s, but resigned in 1977.
Sanders is now a member of the Democratic Socialists of America, an organisation descended from the old Socialist Party of America, but not itself a political party. He contests elections as an independent.
In 1981 Sanders ran for Mayor of Burlington, the largest city in Vermont. He defeated the six-term Democratic incumbent by 12 votes. He won three more terms as Mayor of Burlington, defeating Democratic and Republican candidates.
Sanders stepped down as Mayor of Burlington after eight years in office. In 1986 he ran for Governor of Vermont and came third with 14 percent of the vote. In 1988, he ran unsuccessfully for Vermont's seat in the House of Representatives, polling 38 percent behind the Republican on 41 percent.
In 1990 Sanders ran again, this time successfully. He has held his seat for six successive terms, defeating both Democratic and Republican candidates, and becoming the longest-serving independent member of the House.
Although Sanders is a self-declared socialist, there is little about his politics today to distinguish him from liberal Democrats. He endorsed President Bill Clinton in 1992 and 1996 and Al Gore in 2000. Along with Democratic members of the House, he founded the House Progressive Caucus as a forum for left-wing members of Congress, including Dennis Kucinich of Ohio, who in 2003 became a candidate for President.
Sanders surprised many of his left-wing colleagues by voting in favour of the House resolution supporting the March 2003 Iraq War, although in his speech he was highly critical of the actions of the Bush administration that led to the war.
A left-wing writer, Ron Jacobs of Counterpunch, wrote in March 2003: "It is time the rest of the country wakes up to this truth: Sanders is not a socialist and is not that progressive, especially when it comes to matters of war and peace."