In the prime of his career as a high school teacher and coach, Pat kept having thoughts cross his mind about teaching the Bible in a missions context. He made contact with BMM missionary Tim Whatley and, in the summer of 2001, the Campbells traveled to Urubamba, Peru, where Pat taught a class at the BMM seminary, and he and Wendy assisted local churches.
After just one summer in missions, they were hooked, and the Campbells returned nearly every summer. In 2009 they retired from their previous careers and joined BMM as full-time missionaries to Peru.
The Campbells' second retirement took place in 2022, when they became emeritus BMM missionaries.