Gerald Rau began attending Trinitarian Congregational Church in Wayland MA in seventh grade at the invitation of a friend, committed his life to Christ three years later and rapidly became involved in leadership of both the church youth group and Crossroads, a local Bible study group where he learned how to study the Bible on his own.

As a freshman at Wesleyan University, he was one of the cofounders of the Wesleyan Christian Fellowship (IVCF). During his college days the group grew from the three founders to about 20 students attending regularly. He also assisted with the youth group of Main Street Baptist Church in Meriden CT, and was assistant leader of a Teen Missions International work team one summer.

After graduating from Wesleyan in 1976, Gerald worked for three years at His Mansion, a Christian residential counseling center, at that time in Wauregan CT. In 1980 he moved to the University of Minnesota to pursue graduate work in horticulture. While there, he met his future wife during an outreach to incoming students sponsored by the student fellowship of University Church of Christ (now Southeast Christian Church).

During their respective Ph.D. programs at Cornell, he and his wife helped found the First Ithaca Chinese Christian Church. Gerald wrote the first constitution and bylaws, helped with the incorporation and purchase of the first church building, and preached regularly. He was also a leader of the Cornell Chinese Bible Study on campus. After graduation, he served as the first Director of English Ministries at the Chinese Alliance Church of Westchester in Port Chester NY from 1991-1992.

Moving to Taichung, Taiwan in 1992, he joined Taichung Rung Chung Christian Church. Since 1998 he has been the main speaker at the summer youth retreat 14 times. He also spoke at the Christmas program 8 times and preached and taught adult Sunday school regularly for many years. After a brief hiatus in Michigan and Illinois from 2007-2010, where he was involved with the Ann Arbor Chinese Christian Church and Wheaton Chinese Alliance church, respectively, he returned to Taiwan and has since been an active member of Chuan Ai Baptist Church in Chiayi, while continuing to help from time to time with programs at Rung Chung. Since October 2014 he has led an English worship for international students at Chuan Ai.