This is the kind of pose that requires more in the image, some context to it. What is the vista or subject he is looking at? Mind, I also love this kind of image where you have the person looking out of the edge of the frame, and the context being behind him.
Here though you have a good pose that doesn't work because of the lack of context, so it becomes an image of someone's beard or ear. As a result, the eye is trying to finish the story, and therefore wants to see more of the face.
but for you first portrait, well done, it's great to experiment and make discoveries of how you can tell people's stories.