In the U.S., all people have freedom of religion. Freedom of religion includes all organized religions and smaller religious or moral beliefs. Your employer, supervisor and colleagues cannot treat you differently because of your religion.
Additionally, your employer must make reasonable accommodations and cannot terminate you because of your religion.
What are reasonable accommodations?
You have the right to go to your employer and ask for reasonable accommodations based on your religion. Reasonable accommodations are accommodations that do not cause more than a minimal burden to the company. For example, if you ask to swap shifts with another employee for a holiday, the employer must allow it.
Additionally, you may dress according to your religious beliefs. For instance, an employer cannot discriminate against you for wearing facial hair or certain hairstyles associated with your religion.
How can you prove wrongful termination?
If you go to your employer asking for religious accommodations and terminate soon after, you may be the target of religious discrimination. If your requests do not cause undue hardship for the company, not only can the company not refuse to accommodate you, but the company cannot fire you because of your request or because of your beliefs.
Additionally, the employer cannot demote or remove you from the public eye out of fear of what others may think of you. For example, your employer cannot tell you that you cannot have a public position if you do not remove your religious garb. To prove wrongful termination, you must show that the termination connects to your religious beliefs.
If you have colleagues or clients who do not want to work with you because of your religion, your boss cannot fire you on those grounds.