Roberts was a male Human civilian in the 23rd century. He worked at the Janus VI colony as a miner in 2267.
That same year, he was assigned to guard duty in Chief Engineer Vanderberg's office. He later escorted Doctor McCoy to examine the charred remains of the Horta's most recent kill, Schmitter. (TOS: "The Devil in the Dark")
Roberts was played by background actor Al Roberts who received no credit for this appearance.