This article examines how movement between colonial Liberia and the United States shaped the construction of race through the experiences of one Liberian settler, Samuel F. McGill. In one of the great testaments to race as a social construction, the African neighbors and inhabitants of Liberia, who conceived of themselves as "black," recognized the significant cultural differences between themselves and the newly-arrived African Americans and racially categorized the newcomers as "white." There were significant ramifications for the settlers by becoming simultaneously white and black through their Atlantic mobility. The experiences of McGill highlight this racialized warping and shed light on the effects of movement in the Atlantic world between societies that constructed race differently. McGill is also historically significant as the first African American to receive a medical degree from an American institution, and his access to this education was dependent upon Atlantic mobility and his Liberian residence. McGill's medical education also provides a unique window to view the use of black cadavers for anatomical study and the logistics of the trade in these bodies among doctors and medical schools.