Jeet Kune Do (JKD) is the name Bruce Lee gave to his combat philosophy in 1967. Originally, when Lee first began research into fighting styles, he gave his martial art his own name of Jun Fan Gung Fu. However not wanting to create another style that would share the limitations that all styles have, he instead gave us the process that created it. JKD as it survives today – if one wants to view it "refined" as a product, not a process – is what was left at the time of Bruce Lee's death. It is the result of the life-long martial arts development process Lee went through. Bruce Lee stated that his concept is not an "adding to" of more and more things on top of each other to form a system, but rather, a winnowing out. The metaphor Lee borrowed from Chan Buddhism was of constantly filling a cup with water, and then emptying it, used for describing Lee's philosophy of "casting off what is useless". He also used the sculptor's mentality of beginning with a lump of clay and hacking away at the "unessentials"; the end result was what he considered to be the bare combat essentials, or JKD.

Bruce Lee, and thus JKD was heavily influenced by Western boxing and fencing. Although the backbone concepts (such as centerline, vertical punching, and forward pressure) come from Wing Chun, Lee stopped using the Wing Chun stances in favor of what he considered to be more fluid/flexible fencing and boxing stances. Lee stated that they allowed him to "flow" rather than being stuck in stances. For instance, instead of using footwork to position the body for maximum fighting position vis-a-vis the opponent, JKD uses flowing "entries" that do not require "bridges" from Wing Chun. Bruce Lee wanted to create a martial art that was unbounded and free. Later during the development of Jeet Kune Do, he would expand that notion and include the art for personal development