Lee's lawyers informed reporters of the decision on Monday as prosecutors faced a deadline for filing an appeal to the Supreme Court, which would extend the legal saga over South Korea's largest business group.
They had sought a 9-year prison term for Lee, whose case highlighted often-corrupt ties between the country's family-owned conglomerates and politicians.
The bribery allegation involving Lee was a key crime in the 2016 corruption scandal that ousted Park Geun-hye from the presidency and sent her to prison.
In a much-anticipated retrial of Lee last week, the Seoul High Court found him guilty of bribing Park and one of her close confidantes to win government support for a 2015 merger between two Samsung affiliates. The deal helped strengthen Lee's control over Samsung's corporate empire.
Lee had portrayed himself as a victim of presidential power abuse and his lawyers criticised the ruling. But after mulling his options, Lee decided to “humbly accept” the High Court's decision, his lawyer Injae Lee said.
Samsung did not release a statement over Lee Jae-yong's legal issues. Prosecutors as of Monday afternoon have not revealed whether they would appeal the High Court ruling, which was criticized by some activists as being too lenient.
Lee, 52, helms the Samsung group in his capacity as vice chairman of Samsung Electronics, one of the world's largest makers of computer chips and smartphones.
Aside of the bribery case, Lee has also been separately indicted on charges of stock price manipulation, breach of trust and auditing violations related to the 2015 merger between Samsung C&T and Cheil Industries.
Like other family-run conglomerates in South Korea, Samsung has been credited with helping propel the country's economy to one of the world's largest from the rubbles of the 1950-53 Korean War.
But their opaque ownership structure and often-corrupt ties with bureaucrats and government officials have been viewed as a hotbed of corruption in South Korea.
While never admitting to legal wrongdoing, Lee has expressed remorse over causing “public concern” over the corruption scandal and worked to improve Samsung's public image.
He declared that heredity transfers at Samsung would end, promising the management rights he inherited from his father wouldn't pass to his children.
He also said Samsung would stop suppressing employee attempts to organize unions, although labor activists have questioned his sincerity.
It's not immediately clear what his prison term would mean for Samsung businesswise.
Samsung showed no specific signs of trouble the previous time Lee was in jail in 2017 and 2018, and prison terms have never really stopped corporate leaders from relaying their business decisions from behind bars.
The Supreme Court earlier this month confirmed a 20-year prison sentence for Park for the Samsung case and other bribes and extortion while she was in office from 2013 to 2016.