Who is the founder of judasism?

It depends on how strictly you define Orthodox Judaism.

Orthodox Jews hold that their form of Judaism is the same form of Judaism practiced by the Biblical Patriarch Abraham. As a result, he is the Founder of Orthodox Judaism.

However, Jews did not go around calling themselves "Orthodox" until Samson Raphael Hirsch coined the term in the 1800s as a response to the Liberal forms of Judaism (Reform and Historical-Conservative) that were contemporaneously developing.