Park became South Korea's first democratically elected leader to be forced from office last year when the Constitutional Court ordered her out over a scandal that landed the heads of two conglomerates in jail.
The court also fined Park, the daughter of a former military dictator, 18 billion won ($16.9 million) fine, after finding her guilty of charges including bribery, abuse of power and coercion.
"The defendant abused her presidential power entrusted by the people, and as a result, brought massive chaos to the order of state affairs and led to the impeachment of the president, which was unprecedented," judge Kim Se-yoon said as he handed down the sentence.
The court ruled that Park colluded with her old friend, Choi Soon-sil, to receive 23.1 billion won from major conglomerates including Samsung and Lotte to help Choi's family and bankroll non-profit foundations owned by her.
Prosecutors sought a 30-year sentence and a 118.5 billion won ($112 million) fine for Park.
Park, 66, who has been in jail since March 31 last year, has denied wrongdoing and was not present in court.
The judge said Park had shown "no sign of repentance" but had instead tried to sift the blame to Choi and her secretaries.
Friday's sentence dealt a bitter blow for Park, who returned to the presidential palace in 2012 as the country's first woman leader, more than three decades after she left it following the assassination of her father.
Her ouster from office last year led to a presidential election won by the liberal Moon Jae-in, whose conciliatory stand on North Korea has underpinned a significant warming of ties between the rival neighbours.
Moon's office said Park's fate was "heartbreaking" not only for herself but the nation.
More than 200 supporters gathered outside the court, holding national flags and signs calling for an end to "political revenge" against Park.
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