Marcus lived during the time of the American War for Independence, but had avoided the war to study. One day Bishop and his men, drunk from a massacre in Concorde, turns his brother Silas. Silas however, chose to die with honor and cut his own throat. Not wanting to return empty-handed, Bishop transforms Marcus. A little later Bishop turns Aidan, the perfect soldier, a fact of which Marcus was always jealous.
He works at a local Boston funeral home, covering up murders perpetrated by other vampires. Marcus helps Aidan remove the body of Rebecca, and later nearly gets into a fight with Aidan while trying to assert his authority and often and blatantly tries to one-up Aidan to prove his loyalty to Bishop.
While under the influence of Ray, Josh beats Marcus, overpowering him with his temporarily superhuman strength. Marcus did not take the humiliation well and, without Bishop's orders, he brutalises Josh's sister Emily outside a club. This act, and is failed attempts to lure Aidan back, have caused him to lose Bishop's favour recently. Warned by Aidan, Josh moves with Emily back to the family's house, only for Marcus to follow them. After a brutal fist fight with Aidan, who demands Marcus keep their rivalry between them and keep Josh's family out of it, Marcus retreats.
Marcus is later shown to be in contact with another Vampire coven, The Dutch. It is unknown howewer if Marcus is a formally contacting them on behalf of Bishop or is their spy in Bishop's coven.
He is killed with a stake through the heart by Rebecca to prevent him from killing Aidan, as well as revenge for having been behind the death of Bernie, during Bishop's massacre of The Dutch.
Marcus will be present for season 4.