Cohalan, Daniel Florence (1867–1946), judge and Irish-American leader, was born 21 December 1867 in Middletown, New York, eldest of five sons of Timothy E. Cohalan and Ellen Cohalan (née O'Leary), both Irish immigrants. Educated at Manhattan College, Cohalan graduated in 1885, took a master's degree in 1894, and was given an honorary LLD in 1911. He was admitted to the bar in 1888 and practised law in New York City. He was appointed justice of the supreme court of New York on 18 May 1911 to fill an unexpired term, and was elected to the supreme court in his own right in November 1911. He remained on the bench till resigning on 12 January 1924 to return to private practice. Cohalan was active in Democratic Party politics by 1900, drafting state party platforms and serving as a delegate to the national conventions in 1904 and 1908. He opposed President Woodrow Wilson on a variety of issues, and in 1920 he worked for the nomination of Hiram W. Johnson as the Republican Party candidate for president. Cohalan's quarrels with Franklin D. Roosevelt began in 1910, and he fought Roosevelt's nomination for president in 1932 and 1936. He was also involved in Tammany Hall activities (Grand Sachem from 1908 to 1911), becoming an adviser to party boss Charles F. Murphy and later to John F. Curry (b. 23 November 1873 in Aughantrea, Co. Fermanagh).
An early member of the Clan na Gael, Cohalan, together with John Devoy (qv) and Joseph McGarrity (qv), organised the reunification of that body in July 1900. He helped to form the Sinn Féin League in 1907 and was a key organiser of the Irish Race Convention and the Friends of Irish Freedom (FOIF) on 4–5 March 1916. The FOIF was a large public organisation for revolutionary Irish-American nationalists, created to provide support for the 1916 rebellion in Ireland. When the USA entered the Great War, Cohalan's earlier work to obtain German assistance for Ireland became a liability, but he urged Irish-Americans to support the war effort and to insist that self-determination for Ireland be included among the war aims. Cohalan opposed the peace treaty and the League of Nations, and led an Irish-American delegation to the senate foreign relations committee hearings, contributing to the defeat of the treaty in the senate. When Éamon de Valera (qv) came to the USA in 1919 as president of Dáil Éireann, he clashed with Cohalan, who was by this time the most powerful figure in the Irish-American nationalist movement. Personality and specific visions of Ireland were elements of the growing hostility: Cohalan insisted that Americans must dominate Irish organisations in the United States, while de Valera believed that supporters of Ireland everywhere must follow the elected leaders of Ireland. These differences led to a public fight and a split in the Irish-American nationalist movement, with de Valera creating a new organisation that rivalled the FOIF. In the aftermath of the Anglo–Irish treaty, Cohalan and the FOIF backed Arthur Griffith (qv), Michael Collins (qv), and the Irish Free State. Cohalan visited Ireland in 1923 and supported William T. Cosgrave (qv) in the election of that year.
Cohalan married (1899) a distant cousin, Hanna O'Leary, and, after her death (1911), married her sister Madge in 1915. He had four sons, the Rev. Patrick Cohalan, the Rev. Florence Cohalan, Conn Cohalan, and Daniel F. Cohalan, Jr., and two daughters, Rev. Mother Cohalan and Kathleen Cohalan. He died in New York City on 12 November 1946. The Daniel F. Cohalan papers are in the possession of the American Irish Historical Society, New York.