The court's decision to deny the stay came after 10 p.m. ET, more than three hours after Davis' execution originally was scheduled today. The court did not comment on its decision.
The execution now is expected to occur by 11 p.m. ET.
At 7:05 p.m. ET, five minutes after his scheduled death, Davis' supporters erupted in cheers, hugs and tears outside the jail in Jackson, Ga., as supporters believed Davis had been saved from the death penalty. But Davis was granted only a temporary reprieve as the Supreme Court considered the decision.
Davis was convicted of the 1989 murder of Savannah, Ga., policeman Mark MacPhail, and had his execution stayed four times over the course of his 22 years on death row, but multiple legal appeals during that time failed to prove his innocence.
Public support grew for Davis based on the recanted testimony of seven witnesses from his trial and the possible confession of another suspect, which his defense team claimed cast too much doubt on Davis' guilt to follow through with an execution.
Several witnesses recanted their testimony that Davis fired the shot that killed MacPhail. His impending execution has brought those efforts to a head.
Troy Davis Backers in Frantic Last Minute Efforts to Stop Execution
A growing tide of celebrities, politicians, and social media users called for the execution to be delayed because of "too much doubt" present in his case.
A flurry of messages on Twitter using the hashtags #TroyDavis and #TooMuchDoubt showed thousands of supporters of Davis were intent on flooding the Jackson Distirct Attorney's Office, Georgia Judge Penny Freezeman's office, and the U.S. Attorney General's Office with phone calls and emails to beg for a stay on the execution.
Some users accused Twitter of blocking the topic from trending on Tuesday, though a representative from Twitter told ABC News there was no such action taken. The hashtags were trending today in cities around the U.S. as well as Germany, the U.K., Sweden, and France. Many tweets called the case a symbol of a return to Jim Crow laws and racial inequalities in the justice system.
Big Boi, a member of the group Outkast, tweeted to his followers to go to the Georgia state prison in Jackson to protest the decision. The Roots' Questlove tweeted a similar message.
The NAACP and the Revs. Al Sharpton and Jesse Jackson held a news conference today calling for the execution to be halted.
Amnesty International, which has been fighting on behalf of Davis, encouraged supporters to attend a vigil at the church across the street from the prison at 5:30 p.m. and a protest at 6 p.m., and asked participants to wear a black armband and write on it, "Not in my name!"
Wendy Gozen Brown, a spokeswoman for Amnesty International, said that Troy Davis would want the protests to remain peaceful.
"In this type of situation, there's always the potential for it to go awry, with certain groups, angry rhetoric," Brown said. "But Troy Davis would want people to keep fighting peacefully, for him and for, as he would put it, all of the other Troy Davises out there."
Others who have voiced support for Davis include former President Jimmy Carter, the pope and a former FBI director.
Davis's execution has been stayed four times for appeals since his conviction in 1989, and the Supreme Court gave him a rare chance to prove his innocence last year, but rejected his plea.
A Georgia board of pardons and paroles rejected Davis's plea for clemency on Tuesday.
ABC News' Arianne de Vogue, Steve Osunsami and Michael S. James contributed to this report.