Do first responders need a FCC license for a ham radio to transmit. So if i wanted to call dispatch or another fireman would that be illegal?
The problem is, your question is completely lacking in context, so we can't be certain just what it is you want to know
Do first responders need a ham license to transmit? No.
If you wanted to call dispatch, would it be illegal? Yes... given no other circumstances beyond "you wanted to call dispatch".
Are you a fireman, or a ham? If you're only a ham, your license pertains to Part 97 operations ONLY. End of discussion. If you're a fireman, sure, you can call your dispatcher and don't need a license. Same with calling "another fireman". This assumes you're a fireman who is authorized to use your department's radios.
First responder's radios operate under Part 90. Part 90 contains NO provisions for Part 97 operations. Part 97 contains no provisions for Part 90 operations. If you're a ham operating on Part 90 systems without authorization, you're not in violation of Part 97. You're in violation of Part 90.
Now, what is it you're REALLY asking?