Tom Mercer
Leading from 100 to 8,000 Through Personal Evangelism
About The Episode
In this episode of Leaders in Living Rooms, Sean Morgan sits down with longtime pastor and Oikos Movement founder Tom Mercer to unpack nearly four decades of ministry leadership at High Desert Church and the relational principles that shaped a church of 8,000 in rural Southern California. Tom shares candid stories about longevity, accountability, team chemistry, leadership development, and how the Oikos principle, reaching the world through the natural relationships God has already placed around us, became the backbone of High Desert Church’s growth. From navigating criticism and facility challenges to building a healthy staff culture grounded in prayer and friendship, Tom offers practical, grounded wisdom for leaders pursuing disciple-making and sustainable ministry.
Welcome to Episode 148 of the Leaders in Living Rooms Podcast with Sean Morgan.
Insights from Tom
The Power of Longevity & Thick Skin
Tom entered the lead pastor role at age 29 with only 130 people attending. Over 38 years, he learned that longevity builds trust—not just positional authority. Leading with “thick skin and a soft heart,” he refused to take criticism personally and focused instead on faithfulness and consistency.
Healthy Accountability Protects the Leader and the Church
Tom attributes much of High Desert Church’s stability to hiring strong leaders—especially his longtime executive pastor, Jack—who had permission to call him out. Structures of accountability prevented isolation and ensured humility, even as influence grew.
Relational Culture > Programmatic Strategy
The church’s staff culture centered on friendship, shared life, and prayer. Daily all-staff prayer (8:00–8:45 am), “lunch wagon” outings, and genuine relational connection became the soil where leadership development happened organically. Chemistry and character always outweighed competency.
The Necessity of Focus: One True Priority
Tom teaches that the word “priority” was originally singular, and churches suffer when they attempt to hold multiple priorities. High Desert Church aligned everything around one mission: the Great Commission. This singular focus guarded margin, clarified decisions, and shaped systems that supported disciple-making rather than busyness.
Facility Pain Is Growth Opportunity
High Desert Church’s growth was marked by practical constraints: overflowing rooms, six weekend services, and financial challenges in a low-income region. Instead of resisting discomfort, Tom embraced it as a catalyst for creativity and the next step forward. “Pick your pain—either endure multiple services or choose not to grow.”
Oikos: The Biblical Engine of Disciple-Making
The Oikos principle—reaching the 8–15 people in your relational world—was not a program but a mindset woven into High Desert Church’s DNA. Tom insists that evangelism and discipleship cannot be separated, and that every church already functions as an Oikos church, whether they realize it or not. The movement now resources pastors worldwide to adopt this natural, relational model of disciple-making.
Simplicity Creates Scalability
When ministries overcomplicate their structures, they lose the margin necessary to build relationships and reflect Jesus in everyday life. Tom argues that simplifying programs is essential to strengthening both leaders and congregations.
Episode Links
Not My Church, by Tom Mercer
8 to 15: The World is Smaller Than You Think, by Tom Mercer
If you’re a leader approaching a succession or transition, or maybe you’re a few years in and beginning to see how complex transitions leadership is… go to The Art of Pastoral Succession and check out my course in partnership with Carey Nieuwhof.
Are you in Transition or have one on the horizon? Check out our cohorts and get connected with us at: https://theascentleader.org/cohorts/
Who is Tom Mercer?
Tom has been in pastoral ministry for almost 50 years. For 38 of those years, he served as the Senior Pastor and primary teacher at the High Desert Church in Southern California. During that time, the church grew from 125 to over 14,000 regular attenders, from one campus to four. Tom has also been an ambassador for the oikos principle around the world, frequently speaking at conferences, churches, university classrooms, and denominational gatherings. He currently serves as the President of The Oikos Movement, a non-profit organization committed to helping church leaders become more effective through simplification. Tom received his formal education at Biola University and Talbot Seminary. He is the author of three books, 8 to 15—The World is Smaller Than You Think, Not My Church, and Diary of a World Changer. Tom and his wife Sheryl have been married for 45 years. They have three married children and 11 grandchildren.
Sponsors and Partners
Thanks to our sponsor: OneHope: OneHope’s mission is to reach every child and youth in the world with God’s Word through the global church. In 35 years of ministry OneHope has reached more than 2 billion young people with the Gospel. Learn how you and your church can get involved by visiting onehope.net/learnmore/.
Listen to Recent Episodes
About the Host
Sean Morgan is a coach and speaker with a national reputation as a catalyst of fresh vision. His passion is to help ministries navigate obstacles and turn them into opportunities.
Throughout his career, Sean has pioneered initiatives impacting thousands of leaders across the country. He started out serving as Executive Pastor and CFO at New Life Church in northern California.
As host, Sean gives you access to amazing conversations, hard-won wisdom, and poignant insights from world-class leaders in intimate “living room” settings.
Your Host
Sean Morgan
Leaders in Living Rooms
Craft & Character
Subscribe now on your favorite podcast app
Take Your Leadership to New Heights
The Ascent equips you to lean into your God-given leadership potential.
Cohorts offer you the chance to go deeper with a small circle of peers and professional mentors so you can elevate your expertise and grow your confidence as a leader.
Learn more about upcoming cohorts by clicking below.