My answer is a resounding YES! If I didn't have discipline, I would never have made it through Art School. Working all day and then going to school two or three nights a week, followed by art assignments the other nights and weekends is not for someone who can't force themselves to have good work habits. And it's not easy. There is always something much more enticing to do than buckle down and get the work done.
When we were nearing the end of the courses, one of my teachers told us that although we all were there to learn how to draw and paint . . . how to be artists, only a very small handful of the group would actually follow through and make art a career. He told us that some of us would get discouraged with the near constant rejection . . .boy, he got THAT right! But like other artists, I learned to live with it and celebrate the successes. He said that many of us would start off fine, but would find ourselves getting bored or lonely with the solitary life, the hard work with no certain financial reward when the painting was finished, and we would gradually drift into seeking out fellow artists who were beginning to feel the same way and end up in cafes sipping coffee and talking about art instead of sitting by ourselves day after day, putting paint on paper/canvas, and getting on with our art career. He said that a very few of us would take that lonely, discouraging path and actually become artists. The thing that would make the difference was, you guessed it, DISCIPLINE.
If I don't do the work, I won't have anything to sell, I won't have anything ready when Opportunity comes knocking at my door, (as it often does) and my art will never get any better nor will my career move forward if I don't have the discipline to establish and keep good work habits. I have to work nearly every day, even if I don't feel "inspired". Trust me, NOTHING is more intimidating, more likely to kill inspiration, than that big, blank sheet of white paper sitting on the art table in front of me! Even after all this time, it takes discipline to keep going on a large painting, or on one that is very complicated. The color pattern on this Australian Shepherd nearly caused my eyes to cross, but I wanted to do it and do it well.
Besides painting, I need to have the discipline to market my work, to return calls/emails from potential clients, be cheerful and polite even when I want to say something quite nasty to a rude comment, I need to keep excellent financial records and a record/diary of my completed work.
Sometimes the size and complexity of a painting is nearly enough to swamp me. "I'll Do Hay..." is 20 x 27, nearly the full size of a big sheet of watercolor paper, and there were many times I nearly threw the brush in on this one. I thought it would never be done! But I'm glad I stuck it out and finished it. It never would have happened without the discipline of good work habits.
The bottom line I think, is that if you want something badly enough, you have to be willing to have the discipline to work for it.