My understanding is that at-will states usually override anything in a contract stating to the contrary, unless there is an agreed-upon employment duration (that overrides at-will on both sides, i.e., they can't fire you without compensation), and this is quite rare outside of executives. Not a lawyer, do not rely on this as legal advice, etc.
I mean I don't expect a lot of baseball players or CEO's to be reading my comments, but it's still possible.
IANAL, but there are enforceable terms in employment contracts occasionally. I agree they're rare from my understanding of how things usually wind up shaking out.
Loads of people are singers, actors, voice actors, PR flacks etc., though. All kinds of shows and performances want to hang on to the specific person who is the "face" or voice or otherwise represents a brand.
There is no such thing as an "at-will" state. At-will is the national baseline for employment, states and contracts can add additional requirements on top of it, such as mandatory notice, good-faith exeptions, implied contracts, etc.
All states are "at-will" states. There is no state in the US that over-rides this, and many explicitly state it in their own labor laws. Only company contracts can modify the at-will nature of employment.
Yeah, company contracts can add their own restrictions on top of at-will, and so can state laws.
In 42 states, you can't fire someone for acting in a way that's compliant with public policy, like for saying "I won't ship these defective airplane parts".
36 states have an "implied contract" exception, meaning that if you've informally written or said that you won't quit or fire without good reason, then you can be bound by that as if it were a contract.
11 states have "good faith" exemptions, meaning you can't fire for mean or selfish reasons, like to avoid paying retirement benefits.