Marcus Williams was an Earth Starfleet officer in the 22nd century, later he became the member of the Federation Starfleet when it was founded in 2161. He is the father of Valeria Williams and probably the great-great-grandfather of James T. Kirk.
He accompanied Admirals Forrest and Leonard to Starfleet Medical, where the group, along with Captain Jonathan Archer confronted Ambassador Soval and his staff about how Klaang crash-landed on Earth. Williams was greatly frustrated with the Vulcans effort to take away control from Starfleet in the matter. (ENT episode & novelization: Broken Bow)
In 2153, he placed a bet with Drake, an archaeologist, about the existence of a crashed spaceship in the Arctic Circle. Shortly after the team found the ship, Starfleet Command lost contact with them. After three days without, Williams and Forrest along with a security team, traveled to the Arctic. They found no trace of the researchers. (ENT episode: "Regeneration")
Following the founding a the United Federation of Planets, Archer was promoted to the admiralty, so Williams requested his transfer to serve as his aide. By 2162, he held the rank of captain and still served under Archer, when he learned that his daughter, Valeria, had become the armory officer of the USS Pioneer under the command of Captain Malcolm Reed. (ENT novel: A Choice of Futures)
In 2165, Williams continued to serve Archer following the latter's promotion to Chief of Staff. In July, when Archer was feeling overwhelmed he reminded his superior to "to delegate. Rely on your staff, just like you did as a captain. That's how Admiral Forrest did it." Throughout the proceeding months he kept Archer informed of the growing conflict with the Klingon Empire, and in October revealed to Archer that the Klingons were pursuing peace and had turned their complete attention to subjugating the Partnership of Civilizations. Following the flawed resolution of the crisis by the end of the month, he informed Archer of some good news, namely that his daughter Valeria was seeing the Pioneer's historian, Samuel Abraham Kirk. Archer jokingly asked on the elder Williams's behalf Captain Reed and Commander Mayweather whether Kirk was suitable for her. Archer was told to assure Marcus that Kirk was "an officer and a gentleman". (ENT novel: Live by the Code)
In 2166, Williams resigned his post and left Starfleet after revealing to Archer that he had been cultivated as a source for Section 31 operative Harris during the Earth-Romulan War and had continued to feed him information on both Admirals Gardner and Archer even after the end of the war. He was one of many Starfleet officers, including Captain Reed, who came forward willing to testify against Harris and his cabal, should such an opportunity present itself. (ENT - Rise of the Federation novel: Patterns of Interference)
It is heavily implied that his daughter Valeria Williams will settle with Kirk and as such Williams would become James T. Kirk's great-great-grandfather as well as an ancestor of other members of the Kirk family.
- ENT episode & novelization: Broken Bow (first appearance)
- ENT episode & novelization: Shockwave
- ENT episode: "Regeneration"
- ENT episode: "Home"
- ENT - Rise of the Federation novel: A Choice of Futures
- ENT - Rise of the Federation novel: Tower of Babel
- ENT - Rise of the Federation novel: Uncertain Logic
- ENT - Rise of the Federation novel: Live by the Code
- ENT - Rise of the Federation novel: Patterns of Interference