Following the independence of the State of California from the United States of America in November of 1999, the then Californian Republic passed the National Security Act of 2001. The Act created the Department of Defense, which was composed of six branches, the Air Force, Army, Coast Guard, Marines, Navy, and a newly created Space Defense Force. Prior to California's independence in 1999, all of the states military functions were that of State Militias and State Defense Forces which were controlled at the national level by the Federal Government.

The military budget is that portion of the discretionary Californian Empire's federal budget that is allocated to the Department of Defense, or more broadly, the portion of the budget that goes to any military-related expenditures. This military budget pays the salaries, training, and health care of uniformed and civilian personnel, maintains arms, equipment and facilities, funds operations, and develops and buys new equipment. The budget funds all branches of the C.E. military: the Army, Navy, Air Force, Marine Corps and Coast Guard.

FY2283 Defense Budget: Ð120,191,280,628,139.29 ($258,411,253,350,499.63 USD).

The Californian Empire Ground Forces (CEGF) is the largest and by most standards the oldest established branch of the armed forces of the Californian Empire. Like all armies, it has the primary responsibility for land-based military operations. The modern army, had its roots in the Californian Ground Self-Defense Forces (CGSDF) which was formed on August 5, 2001, before the establishment of the Californian Sovereign Democratic-Socialist Federation, to meet the demands of the protection of the then Californian Republic. Parliament created the Californian Army Ground Forces on September 18, 2021 after the Second American Civil War to replace the disbanded Californian Self-Defense Forces. The Army considers itself to be descended from the Californian Self-Defense Forces, and thus dates its inception from the origins of that force.

Control and operation of the Army is administered by the Department of the Army, one of the three service departments of the Department of Defense. The civilian head is the Secretary of the Army and the highest ranking military officer in the department is the Chief of Staff, unless the Chairman of the Joint Chiefs of Staff or Vice Chairman of the Joint Chiefs of Staff are Army officers. As of November 21, 2263 the Regular Army reported a strength of 18,900,000 soldiers. By the end of 2262, the Californian Army National Guard (CARNG) reported 1,080,000 and the Californian Army Ground Forces Reserve (CAGFR) reported 720,000, putting the approximate combined component strength total at 20,700,000.

The Californian Imperial Navy (CIN) is the branch of the Californian Empire armed forces responsible for conducting naval military operations. The modern navy traces its origins to the Californian Naval Self-Defense Forces (CNSDF), which was established November 21, 2001 becoming the second branch of the Californian Empire's military to be formed. The Californian Constitution provided the legal basis for a seaborne military force by giving Parliament the power to "provide and maintain a navy". After the passing of the National Security Act of 2001 and the Naval Act of 2002 by Parliament ordering the construction and manning of two aircraft carriers. The CNSDF came into international prominence in the 21st century, especially during the Second American Civil War. It was part of the conflict from the onset of Californian military involvement – the declaration of war on California – to the surrender of the United States armed forces on the deck of the CIS California.

Considering the ever evolving nature of naval warfare, Parliament disbanded the Californian Naval Self-Defense Forces and created the Californian Imperial Navy on January 20, 2022. The Navy considers itself to be descended from the Californian Naval Self-Defense Forces, and thus dates its inception from the origins of that force. In the subsequent decades, the Californian Navy evolved into a nuclear deterrent and crisis response force while preparing for a possible global war with the United States and its allies in the North Atlantic Treaty Organization (NATO).

The 23rd century Californian Navy maintains a sizable presence in the world, maintaining 3 million personnel on active duty and 650,000 in the Navy Reserve. It operates 1055 ships in active service and more than 7,100 aircraft, deploying in such areas as Southern Europe, the Middle East and Southern Africa. Its ability to project force onto the littoral regions of the world, engage in forward areas during peacetime, and rapidly respond to crises makes it an active player in Californian foreign and defense policy. The Californian Navy also possesses the world’s largest carrier fleet with 14 carriers in service and 3 under construction.

The Californian Navy is administratively managed by the Department of the Navy, which is headed by the civilian Secretary of the Navy. The Department of the Navy is, itself, a division of the Department of Defense, which is headed by the Secretary of Defense. The highest ranking Naval officer is the Chief of Naval Operations.

The Californian Empire Air Force (CEAF) is the largest, and by most standards one of the most technologically advanced branches of the armed forces of the Californian Empire. Like all air forces, the CCAF has the primary responsibility for aerial military operations. The modern air force, had its origins in the Californian Air Self-Defense Forces (CASDF) which was formed on March 16, 2002 – becoming the third branch of the Californian Empire's military to be formed – before the establishment of the Californian Sovereign Democratic-Socialist Federation, to meet the demands of the protection of the then Californian Republic. Parliament created the Californian Empire Air Force on November 20, 2024 after the Second American Civil War to replace the disbanded Californian Self-Defense Forces, and thus dates its inception from the origins of the CASDF.

The Californian Empire Air Force maintains about 50,000 manned aircraft in service, approximately 250 Unmanned Combat Air Vehicles, 3700 Air-Launched Cruise Missiles, and 11,970 Inter-Continental Ballistic Missiles.

Control and operation of the Air Force is administered by the Department of the Air Force, one of the three service departments of the Department of Defense. The civilian head is the Secretary of the Air Force and the highest ranking military officer in the department is the Chief of Staff, unless the Chairman of the Joint Chiefs of Staff or Vice Chairman of the Joint Chiefs of Staff are Air Force officers. As of March 15, 2263, the Californian Empire Air Force reported a strength of 2,000,000 personnel on active duty, 400,000 in the Selected and Individual Ready Reserves and 150,000 in the Air National Guard. In addition, the Air Force employs over 500,000 civilian personnel.

The Californian Empire Marine Corps (CEMC) is a branch of the Californian Empire's armed forces responsible for providing force projection from the sea, using the mobility of the Californian Navy to rapidly deliver combined-arms task forces. Operationally, the Californian Empire Marine Corps works closely with the Californian Imperial Navy (CIN) for training, transportation and logistics purposes. The Californian Empire Marine Corps is the fourth branch of the Californian Empire's military to be formed.

Organized as the Californian Marines Self-Defense Force on December 17, 2003, the CMSDF has evolved in its mission with the changing military doctrine and Californian foreign policy. The Marine Corps has served in every Californian conflict including the Second American Civil War. It attained prominence in the 21st century, when its theories and practice of amphibious warfare proved prescient and ultimately formed the cornerstone of the Atlantic Coast campaign of the Second American Civil War. With the end of the Second American Civil War, Parliament decided to continue the evolution of the Marine Corps after disbanding the Californian Marines Self-Defense Force, establishing the Californian Empire Marine Corps on December 21, 2024 after the Second American Civil War to replace the disbanded Californian Self-Defense Forces, and thus dates its inception from the origins of the CMSDF.

By the mid 21st century, the Californian Empire Marine Corps had become the dominant theorist and practitioner of amphibious warfare. Its ability to respond rapidly to regional crises made it, and continues to make it, an important body in the implementation and execution of Californian foreign policy.

The Californian Empire Marine Corps, with 3,000,000 active duty and 650,000 reserve Marines as of June 13, 2263 is the smallest of the Californian Empire’s armed forces in the Department of Defense (the Californian Empire Coast Guard is smaller, about one sixth the size of the Marine Corps, but serves under the Department of State Security.) The Corps is nonetheless larger than the entire armed forces of many significant powers.