Fisher was born in Saugerties, New York. His father was a teacher and a Congregational minister, who raised his son to believe he must be a useful member of society. Despite being raised in religious family, he later on became an atheist. As a child, he had remarkable mathematical ability and a flair for invention. A week after he was admitted to Yale College his father died, at age 53. Irving then supported his mother, brother, and himself, mainly by tutoring. He graduated first in his class with a B.A degree in 1888, having also been elected as a member of the Skull and Bones society.:14
In 1891, Fisher received the first Ph.D. in economics granted by Yale. His faculty advisors were the theoretical physicist Willard Gibbs and the sociologist William Graham Sumner. As a student, Fisher had shown particular talent and inclination for mathematics, but he found that economics offered greater scope for his ambition and social concerns. His thesis, published by Yale in 1892 as Mathematical Investigations in the Theory of Value and Prices, was a rigorous development of the theory of general equilibrium. When he began writing the thesis, Fisher had not been aware that Léon Walras and his continental European disciples had already covered similar ground. Nonetheless, Fisher's work was a very significant contribution and was immediately recognized and praised as first-rate by such European masters as Francis Edgeworth.
After graduating from Yale, Fisher studied in Berlin and Paris. From 1890 onward, he remained at Yale, first as a tutor, then after 1898 as a professor of political economy, and after 1935 as professor emeritus. He edited the Yale Review from 1896 to 1910 and was active in many learned societies, institutes, and welfare organizations. He was president of the American Economic Association in 1918. The American Mathematical Society selected him as its Gibbs Lecturer for 1929. A leading early proponent of econometrics, in 1930 he founded, with Ragnar Frisch and Charles F. Roos the Econometric Society, of which he was the first president.
Fisher was a prolific writer, producing journalism as well as technical books and articles, and addressing various social issues surrounding the First World War, the prosperous 1920s and the depressed 1930s. He made several practical inventions, the most notable of which was an "index visible filing system" which he patented in 1913 and sold to Kardex Rand (later Remington Rand) in 1925. This, and his subsequent stock investments, made him a wealthy man until his personal finances were badly hit by the Crash of 1929.
Fisher was also an active social and health campaigner, as well as an advocate of vegetarianism, prohibition, and eugenics. In 1893, he married Margaret Hazard, a granddaughter of Rhode Island industrialist and social reformer Rowland G. Hazard. He died in New York City in 1947, at the age of 80.