Marcus Williams
- Full Name: Marcus Williams
- Born: Iowa, United States of America, Earth
- Species: Human
- Gender: Male
- Daughter: Valeria Williams
- By 2130s: Accepted into Starfleet Training Center (ENT Novel: Tower of Babel)
- Wide receiver on the Academy gridiron football team while in training (ENT Novel: Tower of Babel)
- 2151: Commander, aide, Vice Admiral Maxwell Forrest, Starfleet; San Francisco, United States of America, Earth (ENT: "Broken Bow")
- 2154: Aide de camp, Vice Admiral Samuel Gardner, Starfleet; San Francisco, United States of America, Earth (ENT Novel: A Choice of Futures)
- By 2162: Captain, aide de camp, Admiral Jonathan Archer, Starfleet; San Francisco, United States of America, Earth (ENT Novel: A Choice of Futures, Tower of Babel, Live by the Code)