The answer is no. There are many things you can do with a real estate license. Property management, commercial real estate sales, and in some states, business brokerage are all considered non-weekend real estate careers. This means that most, if not all, of this business is transacted during typical business hours, Monday through Friday 8:00 am to 5:00 pm.
Now, in residential sales, now this is where the water gets a little muddy. People often say that residential real estate sales is the greatest job in the world because you set your own hours. Well, this is true, but most of the business opportunity comes when your clients are most available. While there are exceptions, most Americans are still traditional, Monday through Friday, 8:00 to 5:00 employees. Their free time still tends to be nights, and yes, weekends.
That said, I do know licensees that refuse to work one day of the weekend for personal reasons. They all agree that it does not hinder their business at all. But they let their clients know of the limitations up front and almost always make themselves available the other day of the weekend to care for their clients' needs.