| Sanjunghyun Pres. Ch., KPC, Pusan, Korea | 1963–1965 |
| Community Pres. Ch., unaffil., Mt. Holy, NJ | 1968–1974 |
| Recd. by | PrNJ, OPC | 1969–1969 |
| Reformed Pres. Ch., KAPC, Philadelphia, PA | 1974–1979 |
| Dism. to | KAPC | 1978–1978 |
| Palos Verdes United Ch. (indep.), Palos Verdes, CA | 1979–1982 |
| General Secretary | KAPC | 1979–1984 |
| President | Reformed Pres. Seminary, Los Angeles, CA | 1982–1986 |
| Irvine Central KAPC, Irvine, CA | 1983–1987 |
| Visiting Professor | International Bible College, Los Angeles, CA and Sao Paulo, Brazil | 1985–1987 |
| Founder and President | Pioneer Christian Missions, Irvine, CA | 1987 |
| Associated Missionary | KAPC and OPC | 1988–1991 |
| Dean of Faculty | Korean General Assembly Pres. Seminary, Seoul, Korea | 1988–1994 |
| Christian University Pres. Ch., Chunan, Korea | 1994–1996 |
| President | Christian University, Chunan, Korea | 1995–1997 |
| General Secretary | Assn. of Evangelical Theological Seminary and University in Korea | 1996–1999 |
| President | Christian Theological University, Seoul, Korea | 1997–1999 |
| Visiting Professor | Havarovsk and Vladivostock, Russia | 1997–1999 |
| Professor | Calvin Bible College and Seminary, Los Angeles, CA | 1999 |