well he was 100% For God but alas it was his unwitting "disobedience" that lost him his kingdom,for twice did he unwittingly "disobey" what God told samuel to tell saul to do,and so not only did he lose his kingdom he even didn't get to "add" to his kingdom!
9And it was so, that when he had turned his back to go from Samuel, God gave him another heart: and all those signs came to pass that day. 10And when they came thither to the hill, behold, a company of prophets met him; and the Spirit of God came upon him, and he prophesied among them. 11And it came to pass, when all that knew him beforetime saw that, behold, he prophesied among the prophets, then the people said one to another, What is this that is come unto the son of Kish? Is Saul also among the prophets? 12And one of the same place answered and said, But who is their father? Therefore it became a proverb, Is Saul also among the prophets? 13And when he had made an end of prophesying, he came to the high place.