Youzhny didn't face a break point in beating Haase 6-3, 6-4 in just more than an hour. He lost 13 points over his 10 games serving.
Youzhny made the most of his own break chances, posting a break in each set on just three break-point opportunities.
He improved to 5-0 lifetime versus Haase, who is yet to take a set from Youzhny.
It was the ninth ATP title for Youzhny, whose history in championship matches goes back to a win in Germany in July 2002. He was the runner-up at last month's Gerry Weber Open, which had been his first finals appearance since he won in February 2012 in Croatia.
Youzhny's champion's check for winning the Swiss Open was about $98,000, which pushed his career winnings to more than $10.5 million. Haase is 2-1 in ATP finals. He took home nearly $52,000 Sunday, giving him a career total of about $2.3 million.