Timmerman was last seen in Budapest, Hungary, in early June. On Thursday, he told reporters in Damascus that he had been on a pilgrimage and was detained earlier this year after crossing into Syria on foot from Lebanon.
His resurfacing in Damascus ends months of uncertainty and worry for his family.
"That's what my daughter said, it's a Christmas miracle," his mother, Stacey Collins Gardiner, told NPR.
Locals in the town of al-Thiyabiyah found the 29-year-old man as he wandered barefoot on the streets in the early hours of the morning.