In Star Wars, Qui-Gon Jinn was one of the most independent and inquisitive Jedi of his time, and it was these qualities that would help him decide not to join the Jedi council. However, the deeper reasoning behind that can be uncovered through his younger and more adventurous days as a keeper of the peace.
Before he began training Obi-Wan Kenobi, Qui-Gon was an apprentice to Count Dooku. Preceding his to the Dark Side, Dooku taught Qui-Gon everything he knew about the Jedi. As he got older, though, the young Jedi began to learn more about the Living and Cosmic Force. These concepts would foster Qui-Gon's faithfulness in the Force, a decision that would constantly cause him to disobey the council.
Qui-Gon let the way of the Force guide him and his young apprentice, Obi-Wan Kenobi. The young Jedi saw great potential in his master and believed he should take a seat on the Council, but Qui-Gonn preferred to go his own way, wherever the Force may take him. On more than one occasion, this led him to go against the wishes of his superiors -- a disconnect that would come to a head when he decided to train a young Anakin Skywalker, even after his masters told him the boy was far too old.
Early on, Qui-Gon knew that Anakin was the chosen one, and he believed it was the Force that had to him. So, while he consistently acted as a wild card, Qui-Gon's faith in the Force gave him confidence in all of his decisions. After his death, his belief would pay off when he learned how to become one with the Force, an ability many famous Jedi like Luke Skywalker would go on to use.
While Qui-Gon Jinn only appeared in The Phantom Menace and briefly in The Clone Wars, his character offers the most layered perspective on what it means to be a Jedi. His understanding of the world around him gave him a more freeing mindset, which the Jedi would grow frustrated with. However, that free thought is what gave him the spirit of a Jedi. He understood selflessness in a way many other masters didn't. When it was time for him to take a seat on the Council, his decision to reject the opportunity spoke to more than his independence. He wanted to walk a path closest to the Force, and sitting in a room day in and day out was not where the Force was leading him.
Qui-Gon's death was only the beginning of his journey. His understanding of being one with the Force and manifest as a spirit was not a simple task. However, once he mastered it, he proved that while the Force might be mysterious, it can be understood. In many respects, walking away from the Council was the best decision he ever made for himself, and his selfless mentality would lay the groundwork for the future of the Jedi Order.