Joseph Leonard Walsh, was an American mathematician. His work was mainly in the field of analysis

Mathematical analysis

Mathematical analysis, which mathematicians refer to simply as analysis, has its beginnings in the rigorous formulation of infinitesimal calculus. It is a branch of pure mathematics that includes the theories of differentiation, integration and measure, limits, infinite series, and analytic functions...

.

For most of his professional career he studied and worked at Harvard University

Harvard University

Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...

. He received a B.S. in 1916 and a PhD in 1920. The Advisor of his PhD was Maxime Bôcher

Maxime Bôcher

Maxime Bôcher was an American mathematician who published about 100 papers on differential equations, series, and algebra. He also wrote elementary texts such as Trigonometry and Analytic Geometry. Bôcher's theorem, Bôcher's equation, and the Bôcher Memorial Prize are named after him.-Life:Bôcher...

. He started to work as lecturer in Harvard afterwards and became a full professor in 1935. With 2 different scholarships he was able to study in Paris under Paul Montel (1920-21) and in Munich under Constantin Carathéodory

Constantin Carathéodory

Constantin Carathéodory was a Greek mathematician. He made significant contributions to the theory of functions of a real variable, the calculus of variations, and measure theory...

 (1925-26) as well. From 1937 to 1942 he served as chairman of his department. During World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 he served as an officer in the US navy, was promoted to captain just after end of the war. After his retirement from Harvard in 1966 he accepted a position at the University of Maryland

University of Maryland, College Park

The University of Maryland, College Park is a top-ranked public research university located in the city of College Park in Prince George's County, Maryland, just outside Washington, D.C...

 where he continued to work up to a few months before his death.

Joseph L. Walsh became a member of the National Academy of Sciences

United States National Academy of Sciences

The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...

 and served 1949-51 as president of the American Mathematical Society

American Mathematical Society

The American Mathematical Society is an association of professional mathematicians dedicated to the interests of mathematical research and scholarship, which it does with various publications and conferences as well as annual monetary awards and prizes to mathematicians.The society is one of the...

. Altogether he published 279 articles (research and others) and 7 books and advised 31 PhD students.