In 2268, Marvick worked with Dr. Miranda Jones on the project of adapting starship navigational instrumentation for Medusan operation. On Stardate 5630.7, Marvick, Jones and the Medusan Ambassador Kollos transported aboard the USS Enterprise. Scotty thought that it was a rare privilege to meet him, so much in fact, Scotty bet Marvick a bottle of scotch that he couldn't operate his own instruments manually.
In love with Dr. Jones, Marvick attempted to persuade her to leave the mission she had been assigned to with Kollos and stay with him, an overture she refused. Jealous, Marvick attempted to kill Kollos. The ambassador appeared to Marvick, causing him to go insane and take the Enterprise to an undetermined location outside the galactic barrier. He died soon afterwards in the throes of insanity. An autopsy performed by Leonard McCoy was unable to find a physiological cause for his death, concluding that Marvick "evidently could not live with what he saw."
While visiting the arboretum with Dr. Jones to distract her from Spock's attempts to share Kollos' consciousness, James T. Kirk admonished her not to blame herself for the engineer's actions. Jones explained that she couldn't return his feelings.
Later, fearing for Spock's sanity, Kirk was reluctant to let Jones help his first officer using a Vulcan mind meld, recalling that she had tried to help Marvick, too, and he was dead. Leonard McCoy felt it was different, because Marvick had loved her, but Kirk pointed out that Spock was her rival for Kollos' attention. (TOS: "Is There in Truth No Beauty?")
Marvick was played by actor David Frankham.
In the Star Trek: Enterprise novel Last Full Measure, Marvick appeared in a brief framing sequence. He was seen with an aged Charles 'Trip' Tucker, who had been secretly collaborating with Marvick on the design of the Constitution-class starship.