Gary Michael Hilton waited for Cheryl Dunlap to hike into one of Florida's most secluded forests before killing and then decapitating her body.
"If there was ever a case for the death penalty, this was it," State Attorney Willie Meggs said of the rare unanimous decision in a death case.
In Florida, a judge has the discretion in death cases but is supposed to give "great weight" to the jury's recommendation.
Hilton, 64, had already been sentenced to life in prison in Georgia for pleading guilty to killing 24-year-old hiker Meredith Emerson of Athens, Ga., about a month after Dunlap disappeared.
The headless bodies of both victims were found in forests where Hilton had camped in northern Georgia and the Florida Panhandle.
He is also a suspect in at least three other killings, two in North Carolina and one in Florida.