Painters, writers, and artists do not compartmentalize life; it is the source of their inspiration and their goal is the connection of all of that into their art.

He hardly knows which is which. He simply pursues his vision of excellence through whatever he is doing, and leaves others to determine whether he is working or playing. To himself, he always appears to be doing both. —Lawrence Pearsall Jacks

The basic idea of a portfolio life is that instead of thinking of your work as a monolithic activity, what if you chose to see it as the complex group of interests, passions, and activities it is? And what if instead of identifying with a job description, you began to see the whole mass of things you do as one portfolio of activity?