Galladon's father became an Elantrian while Galladon was still very young. Although, at that time, Elantrians were not required to move to Elantris, it was standard practice for them to live in Elantris to avoid persecution. Galladon lived with his mother and father in Elantris for several years, until his mother died. Following her death, Galladon's father became more and more withdrawn, until he finally died as a result of his depression.
After both of his parents died, Galladon left Elantris, intending never to return.
Galladon was determined to adapt to normal life upon leaving Elantris. Following his father's footsteps, Galladon took up farming, initially farming grain. He built his house all by his own. After several years, he switched to orchards, preferring a crop that did not require planting every year. He continued his tradition of scholarship, reading during the off-season. Unfortunately, despite his best efforts, Galladon never really fit in with his neighbors, and so was able to leave his life with relatively few regrets when the Shaod took him.
A few months after he is taken by the Shaod, Galladon meets Raoden who is running away from five other Elantrians on the latter's first day in Elantris. He starts introducing Raoden to the realities of Elantris, telling him they are already dead and their bodies no longer heal and that the pain drive everyone mad eventually. Raoden offers the food he was given to Galladon in exchange for educating and guiding Raoden for thirty days. Galladon reluctantly agrees. He starts teaching Raoden by showing him how the gangs in Elantris work and how to keep his body from harm as much as possible and talks of the Hoed. He shows the market section, the university and the palace of Elantris where the three gangs make their homes. He tells Raoden when a Seon's master is taken by the Shaod, the Seon is driven mad. After that, he takes them to his father's workroom and introduces Raoden to AonDor by drawing Aon Deo in the air. They start discussing AonDor.
They see the Derethi gyorn Hrathen preaching on the walls of Elantris. Later, they go to the gates and much to Galladon's protest, Raoden rescues a man named Mareshe from the gangs and recruits him. They run from Shaor's men to a building with an unstable staircase. The staircase collapse, Raoden throws the newcomer's food to the men below in the hopes that will make the men leave. They learn Mareshe is a jeweler, but Raoden asks him to make shoes. Mareshe agrees and they start the foundation of New Elantris.
This, however, makes the gangs think Raoden is starting his own gang. They continue recruiting and select a Korathi church as their base. They move Galladon's father's books to this base, though it takes an hour for Raoden to convince Galladon. Soon the Elantrians start coming to New Elantris by themselves and ask to join.
Galladon eventually learns there was a rebellion in his homeland which resulted in the republic collapsing and that Shu-Dereth is the state religion in Duladel. He is deeply shaken by the news. Raoden shows Galladon bags of corn seed and asks how he would judge the quality of the seeds. Galladons finds them satisfactory and soon he plants the corn in one of the gardens and starts growing food.
Galladon is instrumental in Raoden's efforts to establish order in New Elantris. He also explains the concept of the Dor to Raoden and plays a large part in the battle for Teod, organizing and leading the Elantrians who came to Teod's rescue.
Galladon appears as Temoo on Roshar. Purelake fisherman Ishikk calls him Grump. How he is able to move between worlds is unknown. He is described as being dark-skinned, like the Makabaki of Roshar. Unlike the Makabaki, he has thick limbs and a completely bald head. This is very similar to how he is described before the Shaod. Since The Way of Kings takes place after Elantris, it is reasonable to conclude that this is an illusion, either identical or similar to his pre-Elantrian state. Much like in Elantris, he continues to refer to others as "friend", and frequently followed statements with the interrogative "Understand?". Galladon says these in the local language rather than his native Duladel language. At the end of the Interlude, he says a phrase in Duladen, his native language, repeating the word kayana, meaning "crazy". Galladon's true motives on Roshar are unknown, but he and his two companions, Demoux and Blunt, hired Ishikk to look for Hoid. Ishikk was paid with a pouch of spheres even though he wasn't able to locate Hoid in the five months since the trio hired him.