According to most Myers-Briggs Personality Sources, he would be classified as an INFJ.
J.K. Rowling
J.K. Rowling is an INFJ personality type, which is the rarest type.
Donald Trump
As an ENTP, Donald tends to be expressive, curious, and spontaneous. He generally enjoys debating and thinking about issues from different perspectives.
INFP Personality Type
A Mediator (INFP) is someone who possesses the Introverted, Intuitive, Feeling, and Prospecting personality traits. These rare personality types tend to be quiet, open-minded, imaginative, and they apply a caring and creative approach to everything they do.