A jury deadlocked in February over whether to convict him of killing Davis.
He was convicted on three counts of attempted murder for shooting at Davis' friends in the car.
Dunn testified at this month's trial as well as his last that he killed Davis in self-defense after the teen threatened him. He also said he thought Davis had a gun, but no weapon was ever found.
At a press conference after the verdict was read, Davis' father, Ron, told reporters, "We must do a better job of loving each other."
More from the Associated Press:
JACKSONVILLE, Fla. (AP) — A jury has found a Florida man guilty of first-degree murder for fatally shooting a teenager after an argument over loud music outside a Jacksonville convenience store.
The jury reached its verdict Wednesday after more than five hours of deliberations.
Prosecutors say Michael Dunn shot with intent to kill when he fired 10 times into an SUV carrying 17-year-old Jordan Davis and three of his friends in November 2012.
Dunn testified that he thought his life was in danger. Davis was from Marietta, Georgia.
Dunn was convicted previously of three counts of attempted second-degree murder in February and already faces at least 60 years in prison.
The jury in the first trial deadlocked on the first-degree murder count, which led prosecutors to retry him in this case.
source: huffingtonpost.com By Simon McCormack