Or perhaps I'd classify him as the somewhat more sycophantic "longest working genius" or "longest working cool guy". Heck, Knuth was uniquely awarded a master's degree for his bachelor's because his work was considered so outstanding, he's an organist and composer, and he's hilarious. I love this quote about him: "If you had an optimization function that was in some way a combination of warmth and depth, Don would be it."
A quote from him in an interview I found: "Indeed, as mentioned above, my life's work was to be a teacher."