Lieutenant General Jeffrey Oster served in a civilian capacity in Iraq from February through June 2004 as the Deputy Administrator and Chief Operating Officer of the Coalition Provisional Authority (CPA), one of two principal deputies to Ambassador L. Paul Bremer. He remained in Iraq to assist in the transition of governance from the CPA to Iraqi sovereignty and to support the establishment of the US Embassy.

During the last five of his 35 years on active duty, LtGen Oster served and commanded at every level of the Marine Corps Operating Forces. Additionally, he has focused on Christian ministry, philanthropic and service activities, including serving as the chairman of the Executive Committee of the Military Ministry of Campus Crusade for Christ International; as vice chairman of the Board of Governors of the Marine Corps Association; and as vice chairman of the Board of Directors of the Navy Mutual Aid Association.