The 704th Military Intelligence (MI) Brigade's origins can be traced back to 15 November 1954, when, for purposes of creating a carrier unit supporting the National Security Agency (NSA), Headquarters and Headquarters Detachment (HHD) Army Security Agency Troop Command, 7200th Administrative Area Unit, was formed.

The unit was assigned to the Army Security Agency (ASA) and attached to the Second Army for logistical support. HHC personnel were assigned for duty with NSA. The ASA Troop Command had the specific responsibility of supervising the administrative activity of its organic elements. Creation of the ASA Troop Command was the result of a pending move of NSA from Arlington Hall Station, VA, to Fort Meade in early 1955.

At the time of its organization, support personnel of the ASA Troop Command were physically located in Arlington Hall Station. On 26 November 1954, they were relocated to Fort Meade and billeted in (deteriorating) facilities dating back to World War II. In April 1955, the Command moved into recently renovated buildings on Chisholm Avenue. By 30 June 1955, the ASA Troop Command's assigned strength consisted of ten officers and 196 enlisted personnel.

On 26 December 1957, the ASA Troop Command was re-designated as the US Army Security Agency (USASA) Element, NSA (Field), and restructured to include a Headquarters and Headquarters Detachment, A and B Companies, and a company comprised exclusively of Women's Army Corps (WAC) personnel.

Employment of WAC personnel within NSA had actually commenced on 15 October 1957. By mid-1958, more than 60 WACs were assigned. On 14 April 1961, the WAC Company was reattached to US Army Garrison, Fort Meade, for logistical support.

During the period, 1960-1961, the USASA Support Element/NSA underwent a major reorganization. On 1 December 1960, A Company was re-designated as Operations Company; and all personnel serving at NSA were either assigned or attached to Operations Company. B Company was re-designated as Headquarters Company.

On 9 September 1961, the USASA Support Element/NSA was re-designated as US Army Security Agency; however, the designation was short lived. Two years later, on 8 November 1963, it was again re-designated to the USASA Support Group. At the same time, it was reorganized to include a Headquarters and Headquarters Company, Companies A and B, and a Student Company. The Group's assigned and attached strength on 30 June 1964 totaled approximately 1,000. In 1975, Student Company became Company C.

As the years passed, USASA Support Group administrative, training and logistical functions remained essentially unchanged. On 1 January 1977, the USASA was re-designated at the US Army Intelligence and Security Command (USAINSCOM); and, on 1 November 1977, the USASA Support Group was re-designated as the USAINSCOM CONUS Military Intelligence Group.

In April 1978, the CONUS MI Group was tasked with supporting certain aspects of the Peacetime Utilization Program (PUP). In support of this the Group created Companies D and E the latter, for the sole purpose of supporting PUP. Personnel assigned to the 3765th ASA Company was reassigned to Company E when the 376th relocated from Fort Meade to Fort Hood, TX, in April 1978. On 30 June 1979, Company D merged with Company C, and Company E became Company D.

On 31 March 1981, the CONUS MI Group reorganized into two battalions to provide a better span of control and better support to assigned personnel. The 1st Battalion consisted of Headquarters, and Companies A and B; and 2nd Battalion consisted of Headquarters and Operations Company, and Company A. Also as a result of the reorganization, Field Station Key West, FL, became a subordinate unit of the 2nd Battalion. On 9 December 1983, 1st Battalion was deactivated.

There were no further changes until 1 July 1987, when the Military Intelligence Branch became a Corps; and, on 1 January 1988, the CONUS MI Group was re-designated as the 704th Military Intelligence Brigade. The 1st Battalion was re-designated as the 741st Military Intelligence Battalion, and the 2nd Battalion became the 742nd Military Intelligence Battalion.

Field Station San Antonio was absorbed by the 704th MI Brigade and was re-designated as the 748th Military Intelligence battalion. Field Station Key West was re-designated as the 749th Military Intelligence Company and became subordinate to the 748th MI Battalion. A headquarters and Headquarters Company was also created to furnish administrative and logistical support to personnel assigned to the Brigade staff, to all student personnel, and to personnel assigned to 1 remotely situated detachments, which were formed during the period, 1977-1989.

On 3 October 1989, the 704th MI Brigade activated the 743rd Military Intelligence Battalion (Provisional). The 743rd is comprised of a Headquarters and Operation Company (HOC), and Companies A and B. Seven of the Brigade's remote detachments were made subordinate to HOC. Two detachments were re-designated a Companies A and B, respectively; one detachment was made subordinate to Company B; one became a 742nd MI Battalion asset; one reverted to USAINSCOM control; and four currently remain subordinate to HHC, 704th MI Brigade (since reduced to three, following a deactivation).

On 3 October 1990, the 743rd MI Battalion's provisional status was lifted; and, subsequently, a CDPL commander was designated on the FY 92 Lieutenant Colonel command slate.

More recent DoD directed economies in the force structure, prompting the decision to close certain OCONUS installations, led to some further restructuring within the Brigade. On 19 February 1991, the 741st MI Battalion activated Company B for purposes of maintaining command and control of Army personnel employed in the "A" Remote Operations Facility (AROF). Personnel previously assigned to Field Stations Augsburg and Berlin are being reassigned to Company B for duty in the AROF.

On 30 August 1991, the 743rd MI Battalion activated Company C for the express purpose of centralizing administrative control over the Battalion's remote detachments, thus relieving HOC and Company B of that responsibility.

On 1 July 1996, the 748th MI Battalion was realigned under the 702nd MI Group to more effectively align unit missions within the Regional SIGINT Operation Center (RSOC) concept organizational structure. Organizational Changes continued internally within the brigade with the 743rd MI Battalion activating Company D on 22 March 1996 for the purposes of aligning organizational structure to match subordinate unit missions.

In July 1998, the 743rd Military Intelligence Battalion moved from Fort Meade, MD to its present location at Fort Carson, Colorado.

In June 1998, the 704th Military Intelligence Brigade established Company B, 742nd Military Intelligence Battalion to develop a computer network operations force for the Army.  Detachment Meade, 742nd Military Intelligence Battalion was later established to sustain the growing need for an Army computer network operations force.  Detachment Meade was later renamed the Army Network Warfare Detachment in 2007.

In January 2008, the Army Network Warfare Detachment became the Computer Network Operations (CNO) Task Force, and in June 2008, the CNO Task Force was re-designated the Army Network Warfare Battalion (Provisional).

In October 2009, the Army Network Warfare Battalion officially activated, flagged, and became the 744th Military Intelligence Battalion (Army Network Warfare Battalion), later becoming the Army Cyber Brigade and 780th Military Intelligence Brigade on 1 October 2011.

On 25 March 2010, the 704th Military Intelligence Brigade activated the United States Army Technical Support Squadron.

On 1 December 2011, the 744th Military Intelligence Battalion was re-subordinated to the 780th Military Intelligence Brigade and re-designated as the 781st Military Intelligence Battalion. 

While the majority of the 704th Military Intelligence Brigade is located at Fort Meade, MD, its Soldiers are located throughout the United States and the world.