Mubarak joined the Directorate of Public Security Force as a Lieutenant during the period in which the directorate included the partnership of the Kuwait Army and split in 1953. The next year, he was appointed as the first deputy commander of the Kuwait Army.
In 1960, Mubarak founded the Kuwait 25th Commando Brigade, the first designated principle Commando mission initiative of Kuwait prior to the forming of the first Government of Kuwait.
During Operation Vantage, a plan for the defense of Kuwait, Brigadier General Mubarak and Colonel Saleh Mohammed Al-Sabah commanded the Kuwait 25th Commando Brigade and the Kuwait 6th Mechanized Brigade. Following the crisis, Brigadier General Sheikh Mubarak debated with the HM's British Armed Forces on different deterrent strategies to protect Kuwait. A team of British military experts assisted him in organizing the Kuwait Armed Forces, liaising with the British Armed Forces for training. Mubarak acted as commander of the newly formed Kuwait Armed Forces for two years. Later he was promoted to Major General and designated Kuwait's first Chief of the General Staff of the Armed Forces in March 1963, reporting for the first time to a minister following the formation of the first cabinet on 17 January 1962.
In June 1967, the leadership of the Kuwait Armed Forces; from the principle of Arab solidarity; participated in the Six-Day War with several Arab countries against the State of Israel. On the request of minister Sheikh Saad Abdullah Al-Salem Al-Sabah, Mubarak along with his deputy Chief of the General Staff Brigadier General Sheikh Saleh, as acting lead combat commander, assembled an elite task force from various combat units, designated the "Yarmouk Brigade". Accounting for a third of the Kuwait Armed Forces, it deployed to the Egyptian front on May 29, 1967. On the morning of June 5, 1967, the Yarmouk Brigade came under fire, forcing its dispersal. The brigade, intact, regrouped and remained at the Egyptian front from 1968 to 1972 during the War of Attrition between the State of Israel and Egypt that started unofficially a week later.
Ongoing Kuwaiti border disputes with Iraq since Operation Vantage left the majority of the military of Kuwait on alert, deployed all around the Kuwaiti desert. In 1973 the Government of Kuwait; mainly minister Sheikh Saad Abdullah Al-Salem Al-Sabah under the guidance of the Emir of Kuwait; asked Major General Mubarak to assemble a task force to militarily aid the Arab armies deployed on the Syrian front; similarly out of the same principle redeployment of the Yarmouk Brigade engaged on the Egyptian Front in 1973. Taking into account the previous 1967, and current deployment of the Yarmouk brigade on the Egyptian front, he and his deputy assembled a stronger striking force which was designated the Al Jahra Force, which consisted of infantry units, special forces, tanks, artillery, air defense systems and armored brigades. This force was assembled in the Kuwait 25th Commando Brigade and deployed to Syria in two parts on 15 October 1973 with an air component and the majority of the force by land on 20 October. The force gathered in Damascus, and was initially in charge of protecting the capital. The Al Jahra Force later supported the Syrian and Egyptian armed forces on the Egyptian and Syrian front of the war in October 1973 between Arab forces and the State of Israel known as the Yom Kippur War or October War. Mubarak, Saleh and the acting lead combat commander of the Al-Jahra force, led these Kuwaiti forces, in alliance with Iraqi Armed Forces, while at the same time battle-readying the remainder of the Military of Kuwait on the Kuwaiti borders due to the "Sanita" border skirmish.
Joint drills of Kuwaiti and United States Armed Forces (1977)
In 1977, Mubarak Al-Abdullah initiated the first joint drills of the Kuwaiti and United States Armed Forces.
In 1979, Mubarak was promoted to be the first Lieutenant General of the Kuwait Armed Forces. He retired from the military the next year, the first officer to retire from the Kuwait Armed Forces.
