At-will employment means that you can be fired for almost any reason or none at all. Rather than laying out reasons that people can be fired, the government simply mandates why they cannot be fired. You cannot be fire due to something like your gender, your race, your age, and other such protected classes. This is to guard against discrimination.
That said, many companies have established their own policies for firing employees, which may be outlined in a handbook or some other document that employees are given. One common example is the three-stikes rule, which works just as it sounds. Strike One may trigger a written reprimand, Strike Two may bring on a meeting with a supervisor and Strike Three may lead to your firing.
What if you were not given any strikes?
What if your employer just fires you out of the blue, without the three write-ups or warnings outlined in their own policies? If you were guaranteed that process in the handbook, that may be an illegal termination. At-will employment laws weren’t broken, but company policies were, and that’s still illegal. The company had the option not to have those policies at all but chose to enact them anyway. As such, that creates a type of implied contract that the company now has to honor.
Keep in mind that there may be exceptions, such as being allowed to fire an employee on the spot for theft or other serious allegations. Consult your handbook carefully, as every company has its own policies. If your rights were violated when you were fired, then it’s time to look into your options. An employment attorney can help you better understand your position.