The performer, a 20-year old college student, was burned on his hands and chest when his costume caught fire.
"A tree right next to him kind of caught fire and a burst of flames came up and caught him on fire as well," said Kendall Kaiser from Cathedral of Joy.
The actor is expected to recover. Firefighters said the church was using a flammable liquid and recommended against it.
The church said it has changed the way it handles its fires so it doesn't happen again.