Carey Dean Moore has been on death row for almost 40 years.
He was convicted in 1986.
Iwao Hakamada was sentenced to death for murdering a family of four in 1966.
He was pronounced dead at 6.05 p.m.
In denying an appeal from Branch, the Florida Supreme Court noted the extreme savagery of his crime.
Officials in November 2017 struggled for 25 minutes to find a vein to shoot lethal injection drugs into his arm.
His daughter told Newsweek she will be relieved when her father is put to death.
The double execution took place days after the state ended a nearly 12-year hiatus on executing prisoners on death row.