Handling a disrespectful employee can be difficult, especially if he is someone who is an asset to your business. While a difference of opinion will always exist in a work environment, a boss should not tolerate insubordination and disrespect. Although you can fire your employee outright for such impertinent behaviour, you should try to manage the situation first. You do want to send a message to your staff that you are the boss and you will not tolerate disrespect.
Clearly outline to your employee what behaviour is acceptable and what is unacceptable in your business. Be specific and tell him exactly what he is doing that you do not like or approve and how it makes you feel.
Use strong statements when talking to your employee about your expectations. Do not beat around the bush or come off as if you are afraid or begging.
Explain the consequences if the behaviour continues. Make sure the employee understands what will happen if the behaviour continues.
Listen to the employee's grievances and decide whether or not they are valid. Talk to your employee in private so that he will not be humiliated in front of his colleagues.
Impose your penalty immediately if the employee continues this disrespectful behaviour.