Uruguayan rebel leader, founder of the leftist Tupamaro National Liberation Front (1963), a guerrilla movement that waged a relentless battle against the police and the army from 1967 to 1972.

Sendic quit law school in the late 1950s to join the Socialist Party, but when the party was defeated in two elections, he resigned to organize striking sugarcane workers and other rebellious groups. Beginning in the late 1960s, the Tupamaros gained notoriety through such exploits as the distribution of stolen food to the poor, the bombing of an exclusive dance hall, and the 1970 abduction and murder of Dan A. Mitrione, a U.S. advisor to the Uruguayan police force (the events of this kidnapping were the basis of the film State of Siege 【1972】).

In 1970 Sendic was captured, but in September 1971 he and more than 100 other Tupamaros escaped from Punta Carretas Prison by tunneling under the structure to a nearby house. Amid national instability, the Uruguayan police and the army security forces combined to form an antiguerrilla unit which arrested more than 2,000 Tupamaros, including Sendic. In 1973 President Juan María Bordaberry Arocena, backed by the military and acting as their front man, dismissed Congress and reportedly dealt out harsh treatment to Tupamaro prisoners. Sendic, who spent some 13 years in prison before being released under a general amnesty in 1985, later reorganized the Tupamaros as a legal political party.