He served as Corporation Counsel of New York City under Fiorello La Guardia from 1934 to 1937.
[2] He returned to private practice in 1937, while serving as chairman of the New York City Traffic Commission and the Mayor's Committee on Housing Legislation.
[2] He was a partner in the firm of Windels, Merritt, and Ingraham, and specialized in corporate and municipal litigation.
[2] Windels was a delegate to the Republican National Convention from 1920 to 1928 and in 1940, when he was one of the first New York state delegates to support Wendell Willkie's nomination for the United States presidency.
[2] He was chief counsel of the Rapp-Coudert Committee, which investigated the extent of communist influence in the public education system of the state of New York and was responsible for the dismissal of over 50 teachers and clerks at city colleges and public schools for alleged communist sympathies.