Julian Lowell Coolidge (September 28, 1873 – March 5, 1954) was an American mathematician, historian, a professor and chairman of the Harvard University Mathematics Department.

[1] Born in Brookline, Massachusetts, he graduated from Harvard University[1] and Balliol College, Oxford.

[1] He left the private school to accept a teaching position at Harvard and in 1902 was given an assistant professorship, but took two years off to further his education with studies in Turin, Italy[1] before receiving his doctorate from the University of Bonn.

[1][3] Julian Coolidge then returned to teach at Harvard where he remained for his entire academic career, interrupted only by a year at the Sorbonne in Paris as an exchange professor.

[1] During World War I, he served with the U.S. Army's Overseas Expeditionary Force in France, rising to the rank of major.