Holmgren found himself in serious trouble in the first set when Langmo secured a service break to take a 6-5 lead.
The American then had the chance to serve out the set, but Holmgren kept his cool, broke back, and went on to win the subsequent tiebreak.
Langmo stayed competitive in the second set until the score reached 2-2, at which point Holmgren gained the momentum, winning four consecutive games—including two service breaks.
The Dane, who entered the final as the favorite, secured victory on his first match point, defeating the world No. 396, 7-6, 6-2.
The first tournament win this season lifts Holmgren back into the top 200 of the world rankings; earlier this year, he was No. 141 in the rankings
During the tournament, he claimed a win over, among others, 34-year-old Australian Bernard Tomic, who was ranked among the world’s top 20 a decade ago.
Holmgren competes primarily on the Challenger Tour, a circuit that sits below the ATP Tour level.
The Brisbane tournament is a Challenger 75 event—the second-lowest tier on the Challenger Tour—with the winner earning 75 points for the world rankings.
In the coming weeks, Holmgren is set to compete in two additional Challenger tournaments in Australia, giving him the chance to keep his momentum going.
