The TV station said Ruby Zavala was found in a field along County Road 2500 in Winfield. She was taken to a hospital soon after.
KXAS-TV said Jesus Ramirez, 23, was in custody but provided no further details.
Police in Mount Pleasant had been searching for Ruby since Ramirez allegedly kidnapped a mother and her two children at knife-point about 1 p.m. Sunday, KLTV, Tyler, reported.
Ramirez then allegedly let the mother and one child go, but kept the teenager. The car Ramirez was driving was later found wrecked just west of Mount Pleasant.
Mount Pleasant Police Chief Wayne Isbell said Ramirez knows the family and "had at one time a dating relationship" with the victim. Isbell said Ramirez had previously been arrested for sexual assault of a child.
"We do believe he's armed and dangerous," the chief said prior to Ramirez's apprehension.
"We have reason to believe he may be mentally unstable and suicidal."
State authorities had issued an Amber Alert for Ruby, stating she was "in grave or immediate danger," The Dallas Morning News reported.
Notable deaths of 2014 [PHOTOS]