Sardon was a calm, confident CIA representative, a nondescript "grey man in a grey robe" of medium height, medium build and grey hair, who carried "an aura of secret power" about his respectful and unassuming exterior. He described himself as "the least of servants" of the Council, though it was far from the truth. He tolerated the aristocratic Time Lords, believing his sort was the only kind that got things done. As a skilled manipulator he was usually the secret hand in control. Milvo accused him of speaking in paradoxes because his solution to the Players' interference was "to act and not [be seen to] act." Sardon was successful in getting a stay on the Second Doctor's execution because he fit Ragnar's description of the necessary agent: "A person of great intelligence, courage and ability. It will require many kinds of skills, diplomatic and scientific, not to mention a considerable amount of low cunning."
Sardon was an entertaining contrast to the Second Doctor. The two instinctively distrusted each other and were both experts at dissemination. Sardon used appearances to his advantage at every opportunity, and delayed what the Doctor called an urgent report so that the renegade could properly wash up and clean his clothes first. He could accurately gauge the Doctor's mindset by his appearance. He pretended the Doctor was to be executed in hopes he would give up his request to check on the victims of the War Lords but the Doctor saw through his ruse, knowing Sardon did not have a "morbid taste for executions." Until bound with a Time Ring the Doctor was kept under constant armed guards. Sardon accurately guessed he would try to escape and hide with his Shobogan friends. In most of their dealings each fought for what they wanted without conceding to the other. Sardon found the Doctor was capable of irritating him, when he was above that emotion with other Time Lords. In contrast, the Doctor kept him off-balance by being acting greedy for advantage, but bargained his luxuries away for altruistic reasons. He let Sardon choose for himself if his motives were for honor or for selfishness.
As a secret manipulator, Sardon prided himself on self control and abhorred incompetence. The Doctor tested his control a number of times. Learning the Doctor was about to be executed from the folly of a "bungling fool" in Temporal Control caused a rare lapse of panic and ill temper. Despite this loss of face, he insisted on an inquiry to investigate the carelessness that had nearly cost "his" agent his life before he could be put to use. When he learned the Doctor had easily circumvented his security precautions and leaking information of Serena's death to the Capitol guards and her family, he briefly lost his temper but began to realise the Doctor never gave idle threats and gave up.
When the Doctor was theoretically listing the reasons why Sardon could be the agent betraying Gallifrey to the Players, Sardon calmly treated it as an intellectual puzzle, pointing out the strengths and weaknesses of the Doctor's arguments. Together they openly voiced the conclusion that his trusted assistant was the betraying party. Sardon instantly sentenced him to the mind probe and a trial for high treason.
Despite his impeccable manners and ability to accept unwelcome changes in plan, Sardon was merciless and kept the Doctor "on a short leash" in order to reap the benefits of his reluctant service, and employed a young librarian, Serena, to be his keeper during the mission. He persuaded the young woman by offering her power and the backing of the CIA in her bid as Lord President. Had she survived, she would have been a useful tool for their politics. Serena herself had noted that the CIA had participated in the rise and fall of at least two thirds of the successful politicians. (PROSE: World Game)