Yes, your portfolio is always public to your community, you do have the ability to make any specific media private or visible only to you. And when you are ready to share it, you can do that simply by changing the visibility setting while editing that module. This will be visible to employers (if applicable to your network).

PS - If your institution chose to make the portfolio capability public to non-community members, then the visible option (shown below) will make the specific item visible beyond your community also.