C. G. Jung considered Abraham Lincoln to have been a fully developed personality, which makes Lincoln’s life uniquely suitable as a model for the process of individuation. The consideration Lincoln gave to so many conflicting policies and perspectives demonstrates more than mere mental agility—it also indicates his awareness of his shadow side and determination to accommodate internal opposition. His development of so many of his functions and the extensive biographical data available on his life make Lincoln a good subject to illustrate the eight-function model. An analysis of his personality type suggests a hypothetical type of INTP, which is consonant with psychohistorian Michael Burlingame’s assessment of Lincoln’s type. An application of the eight-function model to his life shows how the functions and their archetypes expressed over his lifetime, and how he transformed himself. Lincoln was as imperfect as anyone, but he did not shy away from areas where he lacked expertise. He gave a whole new meaning to the motto, e pluribus unum (“out of the many, one”). He forged a union of many states into a “United States,” and he united his opposing inner voices into an integrated whole.