Thomas M. Gorman joined the Starfleet Marine Corps when it underwent a major period of expansion due to the war with the Cardassians. Joining in 2346, the war forced him to undergo a shortened and rigorous training program before being almost literally thrown into action aboard the destroyer U.S.S. Albany.

After three years on the front lines, during which time he was decorated four times for valor in the line of duty, received the Wounded Lion medal, and promotions to the rank of Captain, he was hand picked to command the brand new (at the time) 21st Marine Training Regiment. This regiment, stationed a mere week's journey from the most intense fighting, was meant created to give new Marines and Starfleet Security personnel a final opportunity to hone their skills at ground combat and starship boarding in hostile conditions. Gorman, with help of his dedicated Regimental Sergeant-Major, Keith DeLollo, established many of the rigorous field exercises used by Starfleet Marine instructors to this day. This earned him additional awards and a fast track to the rank of Lieutenant Colonel.

By 2360, the Cardassian Wars were still being waged and Gorman, by virtue of his exemplary leadership akills, was appointed Commanding Officer of the 5th Marine Division. In addition to being known as a fine leader, Gorman also took many opportunities to further his knowledge and ended up becoming fascinated with intelligence gathering. His understanding of the system, coupled with his ability to train others, resulted in his redesigning of many of the courses tought to incoming Marines specializing in Intelligence and Counter-Intelligence. This led him to be designated the 5th Division's Chief of Intelligence as well as it's Commander. He also, through some additional coursework, managed to become the unit's JAG officer. This was the first and ONLY time that THREE billets in a Marine Division were held by the same officer.

Gorman's affinity with intelligence gathering and his understanding of Federation law managed to attract the attention of senior officers in the Federation Special Security Division. After a series of interviews and screenings, Gorman was placed on a special reserve status within their organization as his proximity to the front lines in the Cardassian War would allow the SSD immediate access to anything he learned about the enemy.

In 2367, Gorman, now holding the rank of full Colonel, was promoted to Brigadier General and relieved of command of the 5th Division. He was hand picked to become the next Chief of Operations for the Starfleet Marine Corps and assumed that duty just in time for the famous Battle of Wolf 359. After that massacre and the U.S.S. Enterprise's successful destruction of the invading Borg vessel, Gorman found himself at the head of an effort to rebuild the Starfleet Marine Corps when its popularity was at its lowest in decades. Despite opinions railing against the continued existence of the Corps, Gorman and an elite team of Public Relations officers managed to boost recruiting and the Corps enjoyed a period in which its numbers swelled to record highs. By the time the Dominion War began, Gorman was promoted to Major General and awarded the Starfleet Marine Medal, the Corps' highest award for performance in non-combat activity well above and beyond the call of duty.

As General Gorman's success had earned him the repect of Marines and Fleet personnel from the freshest graduates of the Academies to the offices of the Marine Corps Commandant and the Starfleet Commander, his work went far from unnoticed within the offices of the Special Security Division. It was at this time that they requested that Gorman consider retiring from the Corps and working for the SSD full-time. Believing that his career as a Marine had brought him as far as he was likely to go (he was not a political sort of man and did not desire to become Commandant), he decied to "quit while he was still ahead," and announced his retirement in September of 2373 after serving for twenty-seven years.

In 2375, Gorman had managed to ascend to the office of the Director of The Special Security Division. Even so, after only two years being retired from the Marines, he longed to put the uniform back on. He placed himself on the SSD active-reserve (though he never officially resigned his directorship) and rejoined the Corps. Unfortunately, his recruiting and PR work had paid off better than he would have wanted as there were no available assignments for an officer holding the rank of Major General! Knowing that it would not affect his retirement plan, he allowed himself to re-enter the Corps as a Colonel in order to fill the only available post for a senior officer: That of Executive Officer of the revamped Starbase Inchon (MSB-601). In addition to serving as XO to Brigadier General Christopher Maxfield (whom he had heard of, but never met before), he was appointed to the post of Intelligence Officer for the 7th Marine Division.

A mere two months after assuming his duties, the tragic events which led to Inchon's disappearance from the known universe occurred. Gorman, reunited with his old friend and SSD protege Keith DeLollo, decided it was in the station's best interest that he make known to his Commanding Officer the fact that he was not retired from the SSD after all. Maxfield ordered the creation of an SSD office within Starbase Inchon and Director Gorman, retired once again from the SFMC, immediately resumed his familiar job of intelligence gathering and Federation law enforcement.