Relin is a graduate of Vassar and was awarded the prestigious Teaching/Writing Fellowship at the Iowa Writer's Workshop. After Iowa, he received a Michener Fellowship to support his groundbreaking 1992 bicycle trip the length of Vietnam. He spent two additional years reporting about Vietnam opening to the world, while he was based in Hue, Vietnam's former imperial capital. In addition to Vietnam and Pakistan, he has traveled to, and/or reported from, much of East Asia.

For two decades, Relin has focused on reporting about social issues and their effect on children, both in the U.S., and around the world. He is currently a Contributing Editor for Parade. For his work as both an editor and investigative reporter, he has won dozens of national awards. His interviews with child soldiers (including a profile of teenager Ishmael Beah, who would later write the bestseller A Long Way Gone) have been included in Amnesty International reports. And his investigation into the way the INS abused children in its custody contributed to the reorganization of that agency.

Relin is currently working on a documentary film about Sherpa mountain climbers. He is also at work on a secret book about food, a children's book with the artist Amy Ruppel, and a novel about Vietnam.