Almost always yes at some level: a local business license from your city or county, state registration if you form an entity, and sales tax registration where your state taxes services. Public spaces add event permits, and none of it is expensive compared to getting caught without it.
The three registrations, sorted
The stack confuses new operators because three different governments each want a different piece. Your city or county issues the general business license, typically a modest annual fee and a form, and it's the one almost every operator needs regardless of structure. Your state comes in twice: entity registration if you form an LLC or corporation, and tax registration, covering sales tax where your state taxes amusement or entertainment services, plus employer accounts once you have crew on payroll. The federal layer is lightest: an EIN, free from the IRS in minutes, which you'll want for banking and taxes even as a sole proprietor.
Home-based operators add one local check: some municipalities want a home occupation permit for businesses run from a residence, usually trivial for an operation whose noise happens in other people's yards.
Where mobile businesses trip
A mobile entertainment business operates everywhere it parks, and a few cities take that literally, requiring a license from out-of-town businesses working inside their limits. Nobody realistically registers in thirty municipalities, and the practical approach is knowing the rules in the three to five cities where your bookings concentrate, especially the larger ones, which are both likelier to require registration and likelier to check.
Public spaces are the sharper edge: parks, beaches, and town greens commonly require event or vendor permits, proof of insurance, and sometimes advance applications measured in weeks. The client who booked the park pavilion often assumes you handle this, and your contract and booking questions should settle who actually does, before the ranger asks.
Getting it done in an afternoon
The whole stack is a short list: EIN from the IRS, entity formation with the state if you're forming one, the city or county license application, and the state tax registration if your services are taxable. Most of it is online, most fees are double digits to low hundreds, and the annual renewals go on the same calendar reminder as the insurance.
Keep digital copies where the business paperwork lives, because the license certificate has a habit of being demanded by exactly the clients you most want: schools, towns, and corporate events all run vendor checks, and the operator who produces clean paperwork within the hour tends to win the booking.
The line to remember
Licensing is an afternoon of forms and a couple hundred dollars, and its real product is eligibility: the schools, parks, and towns that check paperwork are the same clients that rebook every year.