Skating a flawless, though conservative program, Davis and White finished off a climb to the top of their sport. They have been world champions two of the last three years and won the silver medal at the Vancouver Olympics in 2010.
They needed the Olympic title to confirm their lofty position, which is rarefied air for an ice dancing pair from the United States.
Ice dancing has been contested at the Olympics since 1976 and the best any American had done since then was a silver in each of the last two Games.
Davis and White replaced Canadian rivals Tessa Virtue and Scot Moir as Olympic champions, although not by much.
The Americans held a lead of 2.56 points heading into Monday's long program and their effort over four minutes of skating received a score that was 1.97 points better than Virtue and Moir.
That was enough, however, to bring the United States its fifth gold of the Olympics and the 18th medal overall, leaving the Americans tied with Russia for most medals with six days of competition remaining.
The French couple of Nathalie Pechalat and Fabian Bourzat finished fourth while another Russian team made up of Ekaterina Bobrova and Dmitri Soloview came in fifth.