Joash P. Thomas grew up in Mumbai, India, in a family with roots in the St. Thomas Christian community. After immigrating to North America, he earned a master's degree in political management from George Washington University and master's degrees in Christian leadership and systematic theology from Dallas Theological Seminary.

Joash worked as a political consultant and lobbyist in the United States before taking a role with International Justice Mission (IJM), a global, faith-based human rights organization. While serving with IJM, he wrote his first book, The Justice of Jesus (Brazos, 2025). Since then, he has has moved into a role as Director of Fundraising & Advancement and Instructor in Public Theology, Peace & Justice at St. Stephen's University in Nova Scotia.