Doctor M'Benga was a Starfleet medical officer who served aboard the USS Enterprise, under Captain James T. Kirk during his original five-year mission. In the event of Dr. Leonard McCoy's absence, M'Benga was the ranking chief medical officer.

Having interned on Vulcan, he was particularly skilled in treating Vulcans. In 2268, M'Benga treated Spock for a serious gunshot wound. He was noted for slapping Spock violently to bring him out of his Vulcan healing state.

M'Benga examined the body of transporter operator, Ensign Wyatt, who died after being touched by the Kalandan Losira. He concluded that the entire body had suffered cellular disruption.