The teenager, James Yoblonski, reportedly disappeared in a possible attempt live "off the grid."
William Yoblonski, of Reedsburg, said that he was given a polygraph test by the Sauk County Sheriff's Office on Thursday morning, according to WKOW.
The father is reportedly not considered a suspect in the teen's disappearance, according to The New York Post.
“Maybe that’ll relieve people,” he told the outlet. “I had nothing to do with my son’s disappearance.”
Mr Yoblonski said last year that he would remortgage a $10,000 reward for information leading to the return of his son.
He said it has been especially difficult to deal with his son's disappearance knowing that suspicion has been cast on him as the culprit.
“You know you’re innocent but yet here we are doing this [polygraph]," he said following the test.
He said he was surprised by some of the questions that he was asked, such as whether or not he knew where James was, or if he had "anything to do with James' disappearance."
Mr Yoblonski said now that he has passed the polygraph, he hopes that attention will return to his son's disappearance.
“At first, I was upset, but now that I know that proves that I’m innocent and I had nothing to do with it, it’s a relief in a little,” he told WKOW.
Members of the Sauk County Sheriff's Office told WiscNews last month that they believe the teen ran off to become an"off the grid" survivalist.
The 13-year-old reportedly took the family's van and disappeared. When the van was found abandoned later the same day he disappeared, investigators found evidence of a makeshift camp they believed was made by the boy at Devil's Lake State Park.
They also found some of the teen's belongings buried near the site, though they did not find James.
The FBI has not joined in on the investigation since the teen's disappearance.
Deputies are expanding their search beyond the Wisconsin border after finding evidence on his internet search history of methods for traveling out of the state.
“Investigators have followed up with each of these browser searches including physical searches of several areas,” Sauk County Sheriff Chip Meister said. “These follow-ups have not produced any evidence that James was ever physically present at these locations after his disappearance.”
In the meantime, Mr Yoblonski has found himself with few avenues for bringing his son home.
“I don’t know what to do anymore,” he told WKOW. “I just keep looking because it’s all I can do.”
"I just want him home," he said.