Kelner served as Castellan of Gallifrey at the time that the Fourth Doctor returned to Gallifrey to claim the office of Lord President, when the planet was invaded by the Vardans and later the Sontarans. The Fourth Doctor described him as a "jumped-up guard".
Like all Time Lords, Kelner was taken from his family at the age of eight for the selection process in the Drylands. Staring into the Untempered Schism as part of a Time Lord initiation rite, Kelner was inspired by what he saw in the Schism. (PROSE: A Brief History of Time Lords)
Thanks to a combination of good birth and political intrigue, Kelner succeeded Spandrell as Castellan of the Chancellery Guard. To maintain his image, he occupied a new suite of offices made to look overly technological and also established the Castellan's Bodyguard Squad. (PROSE: Doctor Who and the Invasion of Time)
After the Vardan invasion, Kelner assisted the Doctor in removing Time Lords who might oppose the new regime, drawing up lists of those he had a personal grudge against, such as Surgeon General Gomer. At this point, he was told by the Doctor to consider himself as acting Vice President. Although Andred disliked Kelner, he stayed in post because he thought he might be able to lead a resistance movement within the Capitol and act as a foil to the corrupt Castellan. (TV: The Invasion of Time)
Kelner was insecure and attempted to express his power through the Castellan's Bodyguard Squad and his new offices, feeling the need to keep up appearances in a way that his predecessor Spandrell never had. He was far more political and ambitious than Spandrell, (PROSE: Doctor Who and the Invasion of Time) attaching himself to anyone for power and agreeing with them even if their statements made little sense. Kelner was equally at home collaborating with the Sontarans, who had used the Vardans as a cat's paw to their own invasion. (TV: The Invasion of Time)