Reimer next commanded Company C, 11th Battalion, 3rd Brigade, United States Army Training Center, Fort Benning, Georgia from 1966 to 1967.

Reimer returned to Fort Sill as deputy assistant commandant, Field Artillery Center and School from 1983 to 1984.

He served as chief of staff, United States Army Element, Combined Field Army in the Republic of Korea in 1986, followed by assistant chief of staff, C3/J3, Republic of Korea/United States Combined Forces Command from 1986 to 1988.

He received promotion to major general in September 1987 and commanded the 4th Infantry Division (Mechanized) at Fort Carson from 1988 to 1990.

Reimer received his fourth star in June 1991, serving as Vice Chief of Staff of the United States Army from 1991 to 1993.

Reimer has been credited with revamping the Army during a period of high-tempo deployments, including peacekeeping in Bosnia-Herzegovina and Kosovo.

He has also served on the boards of Microvision, DRS Technologies, Plato Learning and Mutual of America Life Insurance.

Reimer is on the Board of Directors for the Arlington, Virginia-based consulting firm Detica, formerly DeticaDFI and DFI International.

He is also serving as the Chairman of the Board for VirtualAgility, Inc. (VA),[3] a software development firm that provides browser-based environments that support interoperation among disparate groups and organizations.

VA systems resolve several of the most urgent challenges currently facing emergency, disaster and business continuity planners.