Bergdahl apparently grew up in a conservative Christian home in Idaho. His parents home schooled him and they attended the Church of the Big Wood, part of the Orthodox Presbyterian Church. (And they are "orthodox"--if you go golfing on Sunday, you might get a visit from one of the church elders.)
Searching for something larger in life, Bowe eventually joined the military. Sometime after beginning a tour of duty in Afghanistan, Bergdahl grew hostile to the mission in Afghanistan. Unfortunate for Bergdahl, as a private citizen you can oppose the political decisions about when and where to deploy troops. As a member of the armed forces, you cannot. He walked off his post and eventually found himself captured by one of the many militias. Read one of the earliest and most thorough accounts here.
Once Bergdahl is released from the hospital, we will learn more.
Bob Bergdahl, his father, has remained fairly conservative during his son's captivity. He has address local Republican Party meetings. And when in Washington DC he worships at Sterling Presbyterian Church, another Orthodox Presbyterian communion. (See its website here.) He apparently grew a beard to chronicle the time that he son spent in captivity and learned Pashto, one of the tribal languages of Afghanistan. He, too, apparently has grown disenchanted with the U.S. mission in Afghanistan. And when he praised god for his son's release in the Pashto language, he created even more controversy. Like most of us average American citizens, Bergdahl is not that "media savvy" perhaps had no clue to the visceral reactions that most American's experience if they saw his appearance.
So what happens when a traitor, or at least a deserter, come home? Usually, that would be a court martial and perhaps a new tour of duty in Leavenworth, Kansas. After President Obama invited the Bergdahl's to the White House for the announcement of their son's release, that scenario has been rewritten.