He has to get a judgment like anyone else. Someone else's judgment doesn't give him a right to collect.
I hate to break it to you, but, yes. You can indeed be sued for legal bills. The attorney has all the pertinent case facts, and experience. Therefore, it is a much simpler process for him/her.
Some attorneys will not try to recover small amounts because it can turn into a malpractice suit,i.e. client says I am not paying because the attorney...
Most states have a system for attorney fee disputes to be resolved through some form of mediation or arbitration. If you are contesting the fees, you should contact your local bar association to find out how to mediate your dispute.
Answer All these answers are correct. It sounds like you already are or are about to be sued for legal fees. If you owe the attorney a fee, than try to work out a payments plan. Be sure to make it a plan you can live with. Most attorneys would rather work things out with their clients than sue them. Just like everyone else they just wanted to get paid for the work they've done.