The hardest part was facing his parents, who were divorced.
"There was always an elephant in the room," he said. "I snooped in my mother's journal one day after I had come out and she'd written, 'I'd rather have found out from a doctor that I had terminal cancer than have a gay son.'"
With his friends, "the thing that struck me most was the isolation," he said. "Before I came out as gay, I had a very busy social life. After I came out, I didn't hear from 95 percent of my friends."
In his book, Kurek stays away from theology. "I want this seen as a people issue," he said. "When we are shunning people, we are shunning Fred and John and Liz and Mary. These are human people."
"In the end it was a book about prejudice, not a book about being gay."
The response to his experience has been positive, according to Kurek. His mother is now supportive of LGBT rights.
Rev. Connie Waters, a protestant minister and LGBT ally from Memphis who met Kurek online when he was questioning his church's view of homosexuality, said she was "proud" of him.
She never encourages her parishioners to lie, but in the case of Kurek's undercover project, it served a "greater purpose."
"For him to appreciate what others went through was essential for him to experience a small part of what those who are LGBT have had to live through to be safe for many years," said Waters.
"The transformation in him was life-changing," she said. "It's what you hope for -- the goal of the Christian walk of faith. It's enough for me that he transformed, but if others learn from him, what an extra blessing that is."