The 9th MSC is engaged throughout the Asia-Pacific realm, providing trained and ready forces to overseas contingency operations, playing a vital role in approximately 20 U.S. Army Pacific Theater Security Cooperation Program exercises, and providing key battle staff in support of Joint Task Force Homeland Defense.

One year later, IX Corps took Command of the Camp Murray staging area in Washington, responsible for training Army National Guard forces, Active Duty and Reserve Units.

Following the attack on Pearl Harbor in late 1941, IX Corps was assigned to defensive duties on the West Coast of the United States.

In 1944 it was deployed to Leyte Gulf, Philippine Islands, where it was placed in charge of preparing the US Tenth Army for the invasion of Okinawa.

An example of which is the Distinguished Service Cross won by IX Corps Commander Lieutenant General Reuben E. Jenkins at Chorwon.

These exercises included the continuing Yama Sakura with Japan, Coral Sands in which IX Corps troops participated in an amphibious as-sault on Molokai with components of the Active Army and Navy, Trupenamt II, and Triad 81 with Australian and New Zealand Forces.

The organization experienced several years of reorganization and restructure to establish a more relevant, ready, and indispensable Pacific Army Reserve Force.