William S. Clark
Born in Kittery Point, Maine, Penhallow graduated from Massachusetts Agricultural College in 1873 (now the University of Massachusetts Amherst). When his former professor, William S. Clark was asked by the Japanese government to assist in the founding of Sapporo Agricultural College (now Hokkaido University), Penhallow accompanied Clark and another MAC graduate, William Wheeler, to teach botany and chemistry. When Clark departed the Sapporo in 1877, Penhallow served as acting President from 1879 to 1880. During his stay in Japan, Penhallow travelled across the archipelago and among other accomplishments became the first westerner to stay with the Ainu peoples.