On his father' side Ustinov is a member of the old Russian nobility. But on his mother's side, he is a member of the Ethiopian Royal Family. The origin of this interracial line was the marriage of his great grandfather, a Swiss military engineer, with the daughter of the Emperor Theodore II. Forbidden to leave Ethiopia, as were the most valued of the Europeans who joined the Imperial service, the engineer had been wedded to the princess, apparently not only in compensation, but to insure his loyalty to the Emperor.

The former Ethiopian legation to Canada, who were then working with the Department of MultiCultural Affairs in Quebec related how, on a number of occasions, they had requested Ustinov to represent Ethiopia to the media in the same way that he had Russia during the years of the cold war when he appeared to be the only cultural liaison between the Soviet Union and the West. Apparently because of the racial climate at the time, Ustinov had not been able to rise to the occasion. Indeed, in his first two autobiographies, he described his great grandmother as a Portuguese woman at the Ethiopian court. It was not until sometime later that he acknowledged his royal genealogy during a CBC Radio interview.