Members of the Brigade performed a wide variety of missions, including the evacuation of prisoners of war, escort of convoys, security of vessels and ports, security of vital installations and VIPs, maintenance of discipline, law and order, and direct support to combat operations. One of the Brigade's finest moments came during the Tet offensive of 1968, when the 716th Military Police Battalion, was the principal force that defeated the Viet Cong attacks across Saigon, including attacks on the US Embassy. The Brigade completed its valiant service in Vietnam and was inactivated on March 20, 1973 in Oakland, California.

The Brigade was re-designated on August 16, 1985 as Headquarters and Headquarters Company, 18th Military Police Brigade and activated in Frankfurt, Federal Republic of Germany. Units of the Brigade deployed in 1991 in support of Operation's Desert Shield, Desert Storm, and Provide Comfort. In August 1994, the Brigade moved its headquarters to Mannheim, Germany. From 1995-1996 the Brigade deployed to Bosnia and Herzegovina in support of Operation Joint Endeavor as part of NATO's Implementation Force. Additionally, units of the Brigade have provided a recurring presence in support of operations in the Balkans since 1995.

The 18th Military Police Brigade led Task Force Summit in 1999, providing security for 49 world leaders in a summit meeting in Sarajevo, Bosnia Herzegovina. The 18th Military Police Brigade was deployed in support of Operation Enduring Freedom and then Operation Iraqi Freedom from February 21, 2003 to February 7, 2004, where it crossed the berm with V Corps and was responsible for military police operations in support of ground combat and eventually the training of the Iraqi police and establishment of the Baghdad Police Academy and police service. Upon return from Iraq in February the Brigade immediately began to prepare for a return to Iraq and was the first Brigade in the army to return to Iraq on November 30, 2004 serving there until November 7, 2005.

While in Iraq, the Brigade was responsible for route security along the main supply routes in and around Baghdad; and was partnered with the Iraqi Police in Al Kut, Al Hillah, Ad Diwaniya, Karbala and Najaf. The 18th Military Police Brigade transformed the Iraqi Highway Patrol from a regional organization of 300 patrolmen to a federal law enforcement agency with national jurisdiction, a new academy and a national headquarters in Baghdad. Additionally, the Brigade took control of all detention operations in Iraq, to include the establishment of Fort Suse, the newest facility in northern Iraq. In September of 2007 to December of 2008 the Brigade Headquarters deployed to Iraq in support of Operation Iraqi Freedom to oversee the training of the Iraqi Police.