Star Wars: How EVERY Jedi Got On The High Council

Eeth Koth is said to have started his training as a Jedi at an older age than most, and because of this he had a much more powerful and mature hold of his emotions than other younglings in the Order.

Because of his emotional control, he was given the rank of Master and found himself on the Council because of his measured assessments of Jedi affairs. He was also one of the few Council members who wanted to see Qui-Gon Jinn train Anakin Skywalker as a Jedi, understanding what it's like to start training later in life.