He falls under the Idealist category because he genuinely seems to believe millionaires are and the like, and his want to advance up the social ladder is not so much for personal gain as it is for winning Daisy's heart.
My dear Carling, I do think it would come as a surprise to you if I told you that many of them heaven knows, are still social climbing and probably because they are not convinced they truly belong and that they have really 'made it.
The same plot features in the film adaptation,.