Nine other officials were sentenced to five months to 12 1/2 years for their roles in the death of Engin Ceber, who was beaten along with two other detainees.
"Public officials are seldom brought to justice for acts of torture and other ill-treatment in Turkey so this really is a landmark verdict," said John Dalhuisen, Amnesty International's Europe and Central Asia program director.
"The fact that a prison director has been found to be responsible for causing death through torture is also very significant."
Serife Ceber, Ceber's sister, said nothing will bring her brother back but hailed the verdict as a step in the fight against maltreatment of prisoners.
Sixty officials went on trial in February -- a retrial made necessary after an earlier verdict resulted in life sentences for four officials was overturned. The fourth official originally sentenced to life received a 2 1/2-year sentence the second time around.
Two police officers were sentenced to 7 1/2 years. Three other prison guards were sentenced to three four-year, two-month terms. A sergeant was sentenced to 2 1/2 years and a prison doctor was sentenced to 1 1/2 months for falsifying records.
Notable deaths of 2014 [PHOTOS]