John Emory McClintock was born on September 19, 1840 in Carlisle, Pennsylvania, the son of John McClintock and Caroline Augusta Wakeman. His father, a devoted clergyman of the Methodist Episcopal Church, taught mathematics, Greek, and Latin at Dickinson College in Carlisle, Pennsylvania. At the age of 14, young Emory (he dropped "John" to distinguish himself from his father) enrolled in the College as a freshman with a concentration in mathematics. He withdrew in 1856 to study at Yale, yet he ultimately received his degree from Columbia University in 1859. He was immediately offered a position as a mathematics tutor at that institution, but the job was short-lived as Emory wanted to further his own education. To that end, he studied chemistry in Paris and London until February, 1862, and also spent a semester in laboratory training at the University of Göttingen, Germany in 1861.
In 1862 he felt an obligation to return to the United States and contribute in some way to the Civil War. He was offered a post as a second lieutenant of Topographical Engineers in the Army, but suffered a debilitating case of sunstroke that forced him to forfeit the opportunity. A very long convalescence ensued, but he eventually made a complete recovery. In 1868, Emory began his career as an actuary with a position in the Asbury Life Insurance Company of New York, finding satisfaction in the application of his mathematical skills to insurance. He switched companies two more times, eventually becoming vice president of the Mutual Life Insurance Company of New York from 1906 until his retirement in 1911.
J. Emory McClintock's insightful thinking in mathematics, especially his theory of "Calculus of Enlargement," earned him distinction in his field and several honorary degrees, including a Ph.D. from the University of Wisconsin in 1884, and LL.D. degrees from Yale and Columbia in 1892 and 1895, respectively. In his lifetime he served as President of the American Mathematical Society and the Actuarial Society of America, being a principal founder of the latter organization. Besides mathematics, his interests included genealogy and military history. He conducted exhaustive studies of his family history in both the United States and Europe, and recorded his findings meticulously. As a member of the Society of Colonial Wars, he also did extensive research on the career of George Washington.
McClintock was married on January 22, 1868 to Zoe Darlington, daughter of John Darlington. They had one son, John, born in 1872, who enjoyed a prominent career in the United States military. After the death of his first wife, Emory married Isabella Bishop, daughter of the Honorable James Bishop. Emory's marriage to Isabella yielded no children. Emory McClintock died on July 10, 1916 at his home in Bay Head, New Jersey at the age of 76.