General Frank J. Grass enlisted in the Missouri Army National Guard in October 1969. He attended the Missouri Army National Guard Military Academy Officer Candidate School and was commissioned in the Engineer Corps in 1981. He has served in a variety of command and staff positions as a traditional National Guard Soldier, in the Active Guard and Reserve program, and on active duty. In his first general officer assignment, he served as Deputy Director of the Army National Guard in Arlington, Virginia.

General Grass served as the 27th Chief, National Guard Bureau and as a member of the Joint Chiefs of Staff. In this capacity, he served as a military adviser to the President, Secretary of Defense, National Security Council and is the Department of Defense's official channel of communication to the Governors and State Adjutants General on all matters pertaining to the National Guard. He was responsible for ensuring that the more than 470,000 Army and Air National Guard personnel are accessible, capable and ready to protect the homeland and to provide combat resources to the Army and Air Force.

Prior to his last assignment, General Grass served as Deputy Commander, United States Northern Command and Vice Commander, United States Element, North American Aerospace Defense Command (USELEMNORAD) at Peterson Air Force Base, Colorado. As Deputy Commander, United States Northern Command, General Grass helped lead the command to anticipate, prepare and respond to threats and aggression aimed at the United States, its territories and interests within the assigned area of responsibility and as directed by the President or Secretary of Defense, provide Defense Support of Civil Authorities, including consequence management operations.

His military awards and decorations include the Defense Distinguished Service Medal w/ Oak Leaf Cluster, Defense Superior Service Medal w/ Oak Leaf Cluster, Legion of Merit, Meritorious Service Medal w/ 3 Oak Leaf Clusters, Army Commendation Medal w/3 Oak Leaf Clusters, Army Achievement Medal, w/ 2 Oak Leaf Clusters, Joint Meritorious Unit Award w/ 2 Oak Leaf Clusters, Army Superior Unit Award, Army Reserve Component Achievement Medal w/ Silver Oak Leaf Cluster and 2 Bronze Oak Leaf Clusters, National Defense Service Medal w/ Oak Leaf Cluster, Global War on Terrorism Service Medal, Armed Forces Service Medal, Humanitarian Service Medal, Armed Forces Reserve Medal w/ Hourglass Device, Army NCO Professional Development Ribbon, Army Service Ribbon, Army Overseas Service Ribbon w/ Numeral 2, Army Reserve Components Overseas Training Ribbon w/ Numeral 2, Danish Home Guard Meritorious Service Medal, Missouri Conspicuous Service Medal (Missouri National Guard), Washington Army National Guard Legion of Merit (State of Washington).