Unlike Maxwell Forrest, his counterpart in a similar universe, Maximilian had a brutal personality. He and Commander Jonathan Archer had an adversarial relationship and clashed on several occasions. After an act of mutiny by Archer, Captain Forrest was thrown into the brig. He later claimed that he chose Archer as his first officer because the commander had no ambition.
Forrest, who had allies of his own on board the Enterprise, retook command of the ship and put Archer in the agony booth. When he discovered that Archer had taken the ship into Tholian space and could not unlock the controls, Forrest decided to carry out Archer's mission, which was to find a Terran ship from the future.
When sending an away team to the ship, Forrest ordered T'Pol to do what she could to make sure that Archer did not come back alive. Shortly thereafter, Forrest was killed in a Tholian attack, choosing to remain aboard the Enterprise while it was destroyed.(ENT: "In a Mirror, Darkly")