Lieutenant Berkley was a Human male Starfleet officer who lived during the mid-23rd century. In 2266, he served in both the sciences and operations division aboard the USS Enterprise under Captain James T. Kirk.
That year, Berkley was the transporter chief when the initial landing party returned from the planet M-113. He reported to the bridge that the landing party had reported one death. He promised to bring the deceased Sturgeon home, after his body was found on the planet's surface.
Later that year, Berkley was again operating the transporter console when the Enterprise visited planet Tantalus V. He embarrassed himself in front of Kirk when he was unable to beam cargo to the Tantalus Penal Colony – and unable to explain the problem until reminded that his destination was a penal colony. At that point, he remembered the security screen in place around such facilities. Kirk advised Berkley to refamiliarize himself with the Manual on Penal Colony procedures. When research material destined for the Central Bureau of Penology in Stockholm was beamed aboard the ship, Berkley left the transporter room to get a vault assignment.
Later, while attempting to break through the force field to rescue Kirk and Doctor Helen Noel from the colony, he apologized to Spock that he just couldn't break through the security screen. After Dr. Noel was able to briefly disrupt the screen from the planet below, Berkley was able to beam Spock directly to the source of the interruption, followed by McCoy and a security detail. (TOS: "Dagger of the Mind")