In a prize which is usually dominated by skiers, Alaba won for the first time in 2013, making this his second time to win the award.
Downhill skier Marcel Hirscher finished just behind Alaba, who won for his leading role both in his club team and for his country over the past year.
The prize was voted for by Austrian sports journalists, and was awarded at the Night of Sports gala evening in Vienna. Because his team is about to take on Borussia Dortmund in the Bundesliga Klassiker on Saturday, Alaba appeared via a video link to accept the award.
The 22-year-old was delighted with his win, saying via the club's official Twitter account, "Sportsman of the Year 2014! I'm overwhelmed! Thank you all."