[6] James had four younger siblings; one brother was philosopher, logician and professor Charles Sanders Peirce (1839–1914).

[3] Another brother was Herbert Henry Davis Peirce (1849–1916) who was the First Secretary of the American Embassy in Saint Petersburg, Russia, at the end of the 19th century.

[3]Like his father, James Mills Peirce became a professor of mathematics and astronomy at Harvard.

[3] He was a preacher in Boston and Charleston, South Carolina, but eventually returned to academia, first as Assistant Professor of Mathematics in 1861.

[3] Among his publications are Mathematical Tables Chiefly to Four Figures (1896)[7] and A Text-Book of Analytic Geometry; On the Basis of Professor Peirce’s Treatise (1857).

Peirce was an early proponent of homosexuality, writing extensively about gay love.