Mo Huanjing, a nanny who started a fire that killed four members of a family in 2017, was executed on Friday morning in Hangzhou, capital of East China's Zhejiang province.
"Mo should be brought to justice for the arson...she committed the act with despicable criminal motives under serious circumstances, resulting in huge social harm and serious consequences," the Supreme People's Court said in a final review which upheld the death sentence.
Although Mo cooperated by confessing to the crime, the severity of the case did not allow for a more lenient punishment, the court said in its review.
Mo's family members refused to meet with her before the execution, although a meeting was allowed by the Hangzhou Intermediate People's Court, which carried out the sentence.
Mo was sentenced to death in February after being convicted of starting a fire in a Hangzhou apartment that killed Zhu Xiaozhen and her three children on June 22.
She appealed the sentence, but it was rejected in June by the Zhejiang High People's Court.
Mo, 35, was burdened with heavy gambling debt and sought nanny positions in 2015 to pay her creditors. In September 2016, she obtained a live-in nanny job at Zhu's home in Hangzhou.
She stole gold jewelry and watches from the family, pawning them for over 180,000 yuan between March and June last year.
On June 22, after losing 60,000 yuan from bad bets, she decided to win Zhu's gratitude and get more money by lighting a fire then putting it out. But the fire spread quickly, forcing an escape from the home. Zhu and her three children died of carbon monoxide poisoning.