Depending on the circumstances of the case, you may have a case of defamation against your employer. If what was said was a false statement made to other people (or placed in your personnel file) and the statement was not an opinion, you might be able to obtain money damages to compensate you for the damage to your career.
The U.S. Supreme Court recently heard a case concerning an airline pilot who sued for defamation. Read more here. In this case, the pilot was pulled off of a flight on which he was a passenger after coworkers reported that he was “mentally unstable” and could be armed. (He was not.) The airline argued that since 9/11, laws encouraging employees to report any strange behavior on airplanes- well founded or not- meant that it could not be liable for being, in effect, too cautious.
In Connecticut, workers can sue and win if their employer fires them for false reasons as long as the employer was reckless in doing so. An example is a worker who was fired for allegedly violating a restraint procedure at a hospital when in fact he did not violate it. The employer claimed he violated the procedure even though it didn’t interview anyone who was actually present during the restraint.