From 1959 to 1994 he was secretary of the Communist Party of El Salvador. In the seventies and eighties he fought as a guerrilla leader of the Farabundo Martí National Liberation Front (FMLN) against the right-wing junta . When the civil war in 1992 ended the FMLN was transformed into a political party with Handal as coordinator. In 1997 he was elected to the National Assembly of El Salvador.
In 2004 he was a candidate for the presidential elections . He called for strengthening ties with socialist -oriented countries in Latin America . According to opponents, he was anti-American . Supporters of Handal accused the U.S. of falsifying the elections, because the U.S. had threatened sanctions to be taken against El Salvador and Handal would win. Eventually he lost the election to Antonio Saca .
On 24 January 2006 , when he returned from the inauguration of Bolivian President Evo Morales , he was at the airport in San Salvador unwell. He was taken to a nearby hospital by helicopter where he died. It was determined that his cause of death a heart attack was.