Abbot Low Moffat was born to a prominent Manhattan family on May 12, 1901 [Unless otherwise noted, all information is taken from the entries on Moffat in Who's Who in the East, 16th ed. (Boston: Larkin, Roosevelt, and Larkin, 1977), The New York Times Biographical Service, vol. 27 (Ann Arbor, MI: University Microfilms International, 1996), 620, and "Abbot Low Moffat", a typescript biographical sketch contained in the Abbot Low Moffat collection folder, M.E. Grenander Department of Special Collections and Archives]. He was educated at Groton School, received his A.B. from Harvard University in 1923, and received his LL.B. from Columbia University in 1926. He was admitted to the New York State bar in 1927. In 1927-1928 he served as an assistant United States attorney for the southeastern counties of New York State, and in 1928-1929 worked as a clerk for the Manhattan law firm of Winter and James.

In 1929, Moffat won election to the New York State Assembly from the Fifteenth Assembly District, which covered part of New York County. He was one of a small group of Republican legislators who wrested control of the Assembly and the Senate from the party's established leadership and enabled the legislature to play a larger role in state politics.

Moffat was assigned a seat on the powerful Assembly Ways and Means Committee and eventually served as its chair (1938-1943). His efforts to rein in the spending of Governor Herbert Lehman were instrumental in giving the legislature a greater say in the shaping of the state's budget. In 1939, the conflict with Lehman culminated in a full-fledged legislative revolt: the Assembly and Senate essentially rewrote the budget that Lehman had submitted. The governor sued, and a state court ultimately upheld the right of the Governor to draft the budget. However, in subsequent decades legislative leaders who followed in Moffat's footsteps gained control over the budget-making process.

Moffat was determined to curb government spending and was a fierce opponent of the governmental centralization implicit in the New Deal [See "Memorandum on Minimum Wage Bills before the New York State Legislature", January 28, 1937; Remarks in Assembly on Social Security bill, February 10, 1937; Press release on the Assembly minimum wage bill, March 17, 1937; and Press release on the Assembly minimum wage bill, March 21, 1937, in Series 1, Press Releases, Speeches, and Reference Material]. However, he pressed for what he saw as prudent government initiatives. He introduced a number of bills designed to halt child labor in New York and other states and replace slum dwellings with suitable public housing [See Press release on Assembly bill barring the sale of goods made by child labor, March 11, 1937, Press release on amending of the Assembly child labor bill, April 5, 1937, Resolution urging the U.S. Congress to pass a bill barring interstate commerce in goods produced by child labor, April 13, 1937, and Resolution memorializing the U.S. Congress to pass a bill barring interstate transportation of goods made by child labor, January 17, 1938, in Press Releases, Speeches, and Reference Material]. He was also instrumental in initiating the construction of a toll road connecting New York City with Albany, Buffalo, and the western New York State-Pennsylvania border: he drafted and co-sponsored the bill that authorized the project, shepherded the bill through the Legislature, and witnessed its signing. He was piqued that the New York State Thruway was eventually named after Governor Thomas E. Dewey, who secured funding for the project.

While serving in the Assembly, Moffat was a delegate to the state's 1938 constitutional convention. He sought to curb government spending and spoke out against a proposed amendment that would have facilitated the state's use of wiretapping in criminal investigations [See Remarks at Constitutional Convention concerning search and seizure proposals, June 27, 1938, in Series 1, Press Releases, Speeches, and Reference Material, 1929-43, Series 3, Constitutional Convention Material, 1938, and clippings in the Constitutional Convention folders, Series 4, Newspaper Clippings, 1933-43].

Moffat also served on the New York State War Council from 1942-1943. He helped to secure funding for child care for female war workers and streamlined the state's revenue flow by backing legislation allowing quarterly payment of state income tax [ See press release on Assembly bill concerning the funding of child care for war workers, March 9, 1943, and press release on Assembly bill concerning child care for war workers, March 22, 1943, in Series 1, Press Releases, Speeches, and Reference Material, 1929-43].

In 1943, Moffat resigned his Assembly seat and took a position with the United States Department of State. He served as the head of the Division of Southeast Asian Affairs from 1944-1947 and in 1946 met with Vietnamese nationalist leader Ho Chi Minh. His reports to his superiors cautioned against Washington's inflexible opposition against nationalist movements in Vietnam and other colonies. Convinced that American statesmen had erred grievously in making anti-communism the cornerstone of postwar foreign policy, he later asserted that it seemed as if the world had been plunged "right back in[to] the wars of religion". In subsequent years, he was openly critical of American involvement in Vietnam.

Moffat was subsequently attached to numerous diplomatic missions in Greece (1947-1948), Great Britain (1948-1950), and Burma (1950-1952). Between 1954 and 1956, he worked for the International Bank for Reconstruction and Development in Washington. D.C., serving as head of the department in charge of the Middle Eastern states. He was then posted to Ghana, where he became head of a survey team for the International Cooperation Administration (1957-1958) and Chief of the U.S. Operations Mission (1958-1960). After leaving Ghana, he served as a representative on a team charged with evaluating the Mutual Security Program (1960-1961) in the Far East.

In 1961, Moffat, who had become a Democrat at the urging of his wife, Marion, retired and moved to Princeton, New Jersey. He published a sympathetic biography of Mongkut, the Thai monarch depicted as a despot in the musical The King and I, and pursued his lifelong interest in genealogical research. [ Abbot Low Moffat, Mongkut: The King of Siam (Ithaca: Cornell University Press, 1961). Moffat had written two histories of his mother's family while serving in the Assembly; see Abbot Low Moffat, Low genealogy; the descendants of Seth Low and Mary Porter (n.p., 1932), and Abbot Low Moffat, Old Low, Old Low's Son-the Descendants of Seth Low and Mary Porter; Low Genealogy, 1807-1956 (n.p., 1956). After his retirement, he completed a study that his father, also an avid genealogist, had begun and undertook a third project. See R. Burnham Moffat and Abbot Low Moffat, Pierreponts, 1802-1962: the American forebears and the descendants of Hezekiah Beers Pierpont and Anna Maria Constable (n.p., 1962); Abbot Low Moffat, A Moffat family record: forebears and the descendants of Reuben Curtis Moffat and Elizabeth Virginia Barclay, 1852-1982 (n.p., 1982)]. In 1973-1976, he was a member of the Princeton Township Committee.

Moffat died on April 17, 1996 at the age of ninety-four. He was survived by his three children, Burnham Moffat, Nancy Moffat Lifland, and Jane-Kerin Moffat.