The answer to this question is not as straightforward as you might think because historians disagree over who they believe is the father of philosophy. For some, Plato, the ancient philosopher from Athens, is often considered to be the most important figure in Western Philosophy. Plato is best remembered for his "dialogues" which laid out his ideas for living socially and understanding the world. Socrates, another ancient philosopher, is mentioned in Plato's dialogues, leading some historians to believe that Socrates is the true father of philosophy. Socrates was the first Greek philosopher and he also worked as teacher in Athens. In fact, Plato was his most famous student.
However, if we are talking about modern philosophy then it can be argued that Rene Descartes is the father. He is a French philosopher from the seventeenth century who is credited with the invention of coordinate geometry and pioneered scepticism, the idea that you can only trust an idea which comes from your own conscious thinking.