Doug was a Vulcan spiritualist who lived during the 23rd century. He was a leading expert on katras, in addition to being a skilled artist, mathematician, and gardener. Doug had a sister named Susan, and a cousin named Pete. He and his sister's parents were drawn to Human names, and he himself was fascinated by Human culture.

Doug had an on-again, off-again romantic relationship with Una Chin-Riley that spanned many years. On one occasion, Chin-Riley stole a shuttle for a romantic rendezvous with Doug in the Skaideion system. Although they shared a strong mutual attraction, they both also felt that they became different people in each other's company, a "wonderful and distracting" effect that led them to want to keep their distance from one another. Until 2261, their last meeting was in 2246, and they parted amicably.

In 2261, Doug resided near Purmantee III. Chin-Riley contacted him for help with Captain Christopher Pike, Lieutenant La'An Noonien-Singh, Ensign Nyota Uhura, and Nurse Christine Chapel, who had been transformed into Vulcans via the Kerkhovian serum for a mission but were refusing to change back. With Doug's guidance, Spock was able to make contact with his crewmates' katras and restore them to their original selves.

Doug was intrigued by Spock's Human attributes, and Spock spent some time teaching him about Humans and Human customs such as the high five and verbal contractions. Chin-Riley, despite her initial intention to resist, elected to renew their intimate association for a night. (SNW: "Four-and-a-Half Vulcans")