She graduated from Barnard College in New York City at the age of 18, gained her Master’s in Economics from Columbia University when she was 19, and had started her career as a professional economist one year later (in 1964, she would earn a Ph.D. from Columbia University as well). In 1936 she married Isaac Schwartz, with whom she raised four children.

Her first published paper appeared four years subsequently, in the 1940 issue of the Review of Economics and Statistics. Written by Arthur Gayer, Isaiah Finkelstein, and, as she then was still known professionally, Anna Jacobson, the paper was on "British Share Prices, 1811 – 1850". That paper was a precursor of several aspects of her subsequent work. An example is the discussion of the change in the behavior of the share price index after 1824.

This change, they showed, told nothing about the British economy or capital markets generally, but resulted from the inclusion of mining stocks – then as now sometimes rather speculative investments. As they wrote, "This example … has been cited to illustrate the need for constant reference to the historical meaning of movements in the indices." The care to put data in its historical context has characterized all her work, and is one of the ways in which it is an example to every economist.

In 1941 she joined the staff of the National Bureau of Economic Research. She has worked in the New York City office of that organization from then right up to the present. When she joined the National Bureau, it was engaged in the study of business cycles. Though she held teaching positions for only a short part of her career she has developed younger scholars by her willingness to work with them and to share her approach, a scrupulous examination of the past, so as both to understand it better and to draw lessons for the present.

In collaboration with Arthur Gayer and Walt Whitman Rostow, she produced the monumental Growth and Fluctuations in the British Economy, 1790 – 1850: An Historical, Statistical, and Theoretical Study of Britain’s Economic Development. It appeared in two volumes in 1953, its publication having been delayed by the war for some ten years after it was completed. That book is still highly regarded among economic scholars of the period. It was reprinted in 1975. Arthur Gayer had died before the book’s first appearance, but the other two authors wrote a new introduction which reviewed literature on the subject published since the original publication date. They admitted that there had developed what they called an "amicable divergence of view" on the interpretation of some the facts set out in the book. In particular, Anna Schwartz indicated that she had in the light of recent theoretical and empirical research revised her view of the importance of monetary policy and her interpretation of interest rate movements.

Years before her first book was reprinted, another economist had joined what might be called the Schwartz team of co-authors. Prompted by Arthur F. Burns, then at Columbia University and the National Bureau, subsequently Chairman of the US Federal Reserve System, she and Milton Friedman teamed up to examine the role of money in the business cycle. Their first publication was A Monetary History of the United States, 1867 – 1960. It hypothesized that changes in monetary policy have large effects on the economy, and laid a large portion of the blame for the Great Depression at the door of the Federal Reserve. That book appeared in 1963, along with the equally famous article, "Money and Business Cycles", which as with her first paper was published in the Review of Economics and Statistics. They also wrote the books Monetary Statistics of the United States in 1970 and Monetary Trends in the United States and the United Kingdom: Their Relation to Income, Prices, and Interest Rates, 1867 – 1975 in 1982.

She also changed minds over financial regulation. Economists, bankers, and policy makers have been and are concerned with the stability of the financial system. Anna Schwartz, in a series of studies in the 1970s, 1980s – in some remarks at a conference in Helsinki – had emphasized that price level stability is essential for financial system stability. The uncertainty engendered by the absence of the first makes the latter unattainable. But even if we have price level stability, from time to time individual financial institutions will fail. Drawing on evidence from over two centuries she demonstrated that such failures do not have major consequences for the economy so long as their effects are prevented from spreading through the financial system. Individual institutions should be allowed to fail, not supported with taxpayer’s money.

There have been other areas of her work including the international transmission of inflation and of business cycles, the role of government in monetary policy, measuring the output of banks, and the behavior of interest rates, on deflation, on monetary standards. She also did work outside of the United States. Some years ago the Department of Banking and Finance at City University, London, England, started a research project on the monetary history of the United Kingdom. For many years, she was an adviser to that project. She commented on papers, suggested lines of approach, came and spoke to students and at academic conferences where the work was discussed.

In 2002 – 2003 she served as President of the International Atlantic Economic Society. Since 2007 she concentrated her efforts on researching US official intervention in the foreign exchange market using Federal Reserve data from 1962. She was not afraid to speak out with respect to the latest financial crisis, and to criticize the government's response to it. She had also addressed a critique of Milton Friedman by Paul Krugman.

She received Honorary Degrees from: University of Florida (1987); Stonehill College, Massachusetts (1989); Iona College (1992); Rutgers University (1998); Emory University (2000); City University of New York Graduate Center (2000); Williams College (2002); Loyola University Chicago, 2003; City University Business School, London (2006)