Legal Question in Business Law in California

Yes.

Actually, you might need a general contractor's license for that. You would definitely need at least a painting contractors' license.

If you are the person advertising, obtaining jobs, dealing with clients and hiring the labor, then you are the contractor and need a Painting and Decorating Contractor's license (not a general contractor's license). It can be issued to a company or an individual. Generally, there is no requirement that painters be licensed in California. You only need a contractor's license if you do jobs that are over $500 each (and you are not allowed to split large jobs into several smaller ones to achieve that rate). Whether you do large or small jobs, you will need a business license (issued by your local city) and, if you employ people, you need to register as an employer with the state of California (and have workers comp insurance and unemployment insurance).