Command Sergeant Major Timmer entered the military in June 1978. After completing Basic and Advanced Individual Training at Fort Gordon Georgia, he was assigned to B Troop 1st of the 4th Cavalry, 1st Infantry Division, Fort Riley Kansas. CSM Timmer was later assigned to C Troop 1st Infantry Division Forward in the Federal Republic of Germany.
Upon completing his first three year assignment with a signal MOS, CSM Timmer re-enlisted for the Military Police Corps. Upon completing Advanced Individual Training, he was assigned to the 293rd Military Police Company, 519th Military Police Battalion, Fort Meade Maryland. In 1983, CSM Timmer left active duty and re-enlisted in the Reserve.
His first assignment was with the 8830th Military Police (OSUT) Brigade, Fort Meade Maryland. Later assignments include, HHC 8830th Military Police Brigade, HHC 220th Military Police Brigade, S-3 OPS SGM, 200th Military Police Brigade, the 400th Military Police Battalion CSM, 220th Military Police Brigade CSM, 99th Regional Readiness Command CSM and on 1 Oct 2008 he was assigned as the CSM of the 99th Regional Support Command. On 1 Dec 2010 he was selected as the CSM for the 200th Military Police Command.
Command Sergeant Major Timmer is a graduate of the United States Army Signal School, Military Police School, Instructor Training Course, Battle Focused Instructors Course, Primary Leadership Course, Basic Noncommissioned Officers Course, Advanced Noncommissioned Officers Course, Terrorism – Counter Terrorism Course, First Sergeants Course and the United States Army Sergeants Major Academy.
Among his many assignments, he has worked as Communications Chief, Patrol Supervisor, Desk Sergeant, Instructor, Senior Instructor, Chief Instructor, First Sergeant and Operations Sergeant Major. While assigned to the 400th Military Police Battalion, as the Battalion CSM, he was activated for Operation Noble Eagle.
In December 2002, CSM Timmer was assigned to the 220th Military Police Brigade, and in January 2003 was activated with the Brigade for Operation Enduring Freedom/Operation Iraqi Freedom. Command Sergeant Major Timmer has been decorated with the Combat Action Badge, Bronze Star, Meritorious Service Medal with Oak Leaf Cluster, Army Commendation Medal with Oak Leaf Cluster, Army Achievement Medal with 3 Oak Leaf Clusters, Good Conduct Medal, Army Reserve Achievement Medal with 5 Oak leaf Clusters, National Defense Service Medal with Bronze Star, The Global War on Terrorism Expeditionary Medal, The Global war on Terrorism Service Medal, Humanitarian Services Medal, Army Forces Reserve Medal with Hour glass, M device and the Number 2 affixed, Noncommissioned Officers Professional Development Ribbon, with 4 affixed, Army Service Ribbon, the Overseas Service Ribbon and the Army Reserve Components Overseas Training Ribbon.