Normally, an agent for a disclosed principal can bind the principal by the agent's signature. In a corporate employee scenario, if the employee has apparent authority to sign (e.g. because they are a corporate officer or director) the corporation may found itself bound.
What the entity wants to avoid is that it is bound becuase some employee decided to sign a contract without apparent authority and against the wishes or judgment of those with the actual authority to make that decision. You were told not to do it and you did it. If you got oral consent instead of written consent, then the line is more blurred.
As an employee in an "at will" employment state, you can be fired for no reason or for a reason (but not because you belong to a protected class, e.g. race, religion, etc.) Unless you have contractual protections (or belong to a union) you will have an uphill battle regarding your termination.
Answered on Feb 27th, 2015 at 1:36 PM