(For a note of clarification, the Professor Higgins that we have in mind is his portrayal by Leslie Howard in the 1938 film, Pygmalion.)
Professor Higgins fits the Old Knock type very nicely. He is obsessed with his scholarly work as a linguist—often time to the detriment of those around him. He is a man of means, he knows how to live the fashionable life, but he is more interested in his intellectual pursuits. He is also a Romantic. Although appearances seem to the contrary, he firmly believes that he can turn a common street urchin into a true lady—and does so.