Mr. Bordaberry had been serving a 30-year sentence under house arrest for orchestrating the coup and for crimes against humanity. He was found guilty of 14 deaths and disappearances related to the dictatorship.

His years as president, between 1971 and 1976, are remembered as perhaps the bleakest in Uruguay’s history, marked by a wave of disappearances, torture and killings intended to wipe out the remnants of the leftist Tupamaro guerrilla movement.

Born into a wealthy cattle ranching and political family on June 17, 1928, Mr. Bordaberry entered politics through a conservative rural movement, founded in 1951, of which his father, Domingo, was a prominent member.

With backing from the movement, Mr. Bordaberry became a senator and a leading figure in shaping rural policies in the late 1950s and the 1960s. Mr. Bordaberry served as agriculture minister from 1969 to 1971 during the presidency of Jorge Pacheco of the centrist Colorado Party, which is now run by Mr. Bordaberry’s son Pedro.

Hand-picked by Mr. Pacheco, Mr. Bordaberry ran for president in 1971 and won in a tight vote that was criticized as being tarnished by fraud.

He filled his administration with civilian and military conservatives. Faced with rising inflation, a weakening economy and opposition from militant groups, he pressed forward with his predecessor’s authoritarian politics, which included the suspension of civil liberties and the imprisonment and killing of opposition figures.

In 1973, his vice president quit and the military started questioning Mr. Bordaberry’s decisions. The military threatened to oust Mr. Bordaberry unless he ceded more power to them.

On June 27, 1973, Mr. Bordaberry dissolved Parliament and suspended the Constitution, along with political parties, social organizations and additional civil liberties.

Although he remained president, tensions with the military continued to grow. Military leaders cut short his term in 1976, replacing him with a leader thought to be less resistant to their orders. “When he was no longer useful as a puppet for the security forces — among the most brutal in the region — they unceremoniously ousted him from power,” said Riordan Roett, who heads the Latin American studies program at Johns Hopkins University.

Mr. Bordaberry went back to his ranch after his dismissal. He did not return to the public eye until 2006, when President Tabaré Vázquez led investigations into human rights abuses under Mr. Bordaberry’s government.

In Argentina, state security forces are estimated to have abducted and killed as many as 30,000 people; in comparison, the number of people who disappeared in Uruguay while Mr. Bordaberry was president — both before and after the military stripped him of his authority in 1973 — has been estimated at 210.

In 2010, Mr. Bordaberry was sentenced to 30 years in prison for violating the Constitution by participating in the coup. He served three months in prison before being transferred to one of his son’s homes in Montevideo, the capital, because of failing health.

Mr. Bordaberry is survived by his wife, María Josefina Herrán Puig, and several children.