Born 900 years before the Battle of Endor, Yoda belonged to an ancient and mysterious species. As he was keenly attuned to the Force, he joined the Jedi Order as a youngling. After undergoing the ritual known as the Gathering, he received his kyber crystal, and Professor Huyang helped him construct his first lightsaber aboard the Crucible. Thereafter, Yoda was paired up with a personal mentor. During their time together, Yoda's Jedi Master told him the tale of K'ungfu and Chuang, two great Jedi of the past. Around the age of 100, Yoda was ready to pass on what he had learned. Having attained the rank of Master, he would spend the next eight centuries training and tutoring generations of Jedi. It was estimated that over his lifetime, he trained around 20,000 Jedi.
Centuries later, Yoda would take on the human Dooku as his last known padawan in the era of the Galactic Republic. During one mission to the Wookiee homeworld of Kashyyyk, the padawan witnessed his master face off with a giant, dreadful terentatek.
Yoda would visit Kashyyyk on several other occasions prior to the Battle of Kashyyyk, serving as Jedi negotiator in many incidents involving the Wookiees and their Trandoshan neighbors. This earned him the ancient title of "Defender of the Home Tree", as well as becoming a member of many Wookiee leaders' and all the inhabitants of Kachirho's honour families.
Yoda also taught outside the Master/Padawan relationship, and trained all the Jedi Younglings prior to their teaming up with Jedi Masters, including Master Obi-Wan Kenobi, Kanan Jarrus, as Caleb Dume, often heard Yoda counsel "Do, or do not. There is no try." He also taught groups of younglings in the basics of Jedi training, including lightsaber instruction.