The 19-year-old clinched the title after Ruud’s backhand went wide.
“He played amazing tennis all week,” Ruud said. “I can’t be too upset about my loss.”
The 182nd-ranked Seyboth Wild, who beat Argentina’s Renzo Olivo in Saturday’s semifinals, is set to rise to No. 113 on Monday.
Ruud was playing in the second final of his career in two weeks. He won the Argentina Open in Buenos Aires on Feb. 16, becoming the first Norwegian to win an ATP tour singles title.