He was born on September 16, 1852, in Brooklyn, New York City. His father was Rudolph Lexow (1823-1909) who was born in Germany. His mother was born in England and had died prior to 1880. His siblings include: Charles K. Lexow (1850–1928) who was a lawyer in 1880; Allen Lexow (1855-?) who was a banker in 1880; and Rudolf Grant Lexow (1865-?).
He studied abroad and at the Columbia Law School, where he graduated in 1872. He was admitted to the bar and established his practice in New York City, where he had many German-American clients. In 1880 Clarence was living in Clarkstown, Rockland County, New York with his parents, and he was already a lawyer. Rudolph Lexow, his father was working as an editor. Clarence and Charles also appear as living in Manhattan in the Benedict Building at 79 Washington Place in New York City.
In 1882, he became a resident of Nyack and was active in the Republican Party there. In 1890 he was an unsuccessful nominee for Congress. Though Lexow was unsuccessful, the majority for the Democratic victor was lower than had been usual.
He was a member of the New York State Senate from 1894 to 1898, sitting in the 117th, 118th (both 16th D.), 119th, 120th and 121st New York State Legislatures (all three 23rd D.). Here he at once took a leadership role, and was chairman of the committee on internal affairs and introduced the bi-partisan police bill calling for an investigation of the New York City Police. This led to the appointment, in 1894, of the Lexow Committee, of which he was head. The committee documented how Tammany Hall leaders and the police extorted bribes from operators of gambling and prostitution houses. He was a Senator from the 16th District from 1894 to 1895; and the 23rd District from 1896 to 1898. Lexow was also the introducer of the bill creating the city of Greater New York, was chairman of the joint legislative committee for the investigation of trusts and unlawful combinations, of the committee on primary elections reform, and of the judiciary committee.
In 1896, he was chairman of the committee on resolutions at the Republican State convention and introduced the gold standard plank in the platform; in 1900, he was a presidential elector, voting for William McKinley and Theodore Roosevelt.
He is author of reports on:
- Municipal Government (5 vols., 1895)
- Trusts and Unlawful Combinations (1895)
- "Ex-Senator Lexow, Investigator, Dead". New York Times. December 31, 1910. Retrieved 2007-03-08.
Headed Famous Inquiry Into Now York City Police Department in 1834. Notable Career in Senate. Author of Bills Extending Anti-Trust Laws and Primary Reform Legislation, Robin Company Director.
- "C. K. Lexow Dies of Heart Attack". New York Times. July 14, 1928. Retrieved 2007-03-08.
Commissioner of Supreme Court Records Was Found Stricken in His Office Thursday. In Politics for 47 Years. Oldest Republican District Leader in New York City. Brother of Late Clarence Lexow. A Native of New York City. Entered Politics in 1881. Charles K. Lexow, Commissioner of Records of the Supreme Court, died yesterday afternoon at Beekman Street Hospital. He had been taken to the hospital Thursday morning after a cleaner had found him helpless in a chair in his office in the Hall of Records.
- Rines, George Edwin, ed. (1920). "Lexow, Clarence". Encyclopedia Americana.
- Clarence Lexow, Report and proceedings of the Senate Committee appointed to investigate the Police Department of the city of New York, 1895
- Isabelle Keating Savell (1905-?), Politics in the Gilded Age in New York State and Rockland County; A Biography of Senator Clarence Lexow
- Cops, Crooks, and Criminologists. An international biographical dictionary of law enforcement. By Alan Axelrod and Charles Phillips. New York: Facts on File, 1996
- Dictionary of American Biography. Volumes 1-20. New York: Charles Scribner's Sons, 1928–1936
- The National Cyclopaedia of American Biography. Volume 5. New York: James T. White & Co., 1891. Use the Index to locate biographies
- Who Was Who in America. A component volume of Who's Who in American History. Volume 1, 1897-1942. Chicago: A.N. Marquis Co., 1943
- "SENATOR LEXOW TO GERMANS; He Tells Them that Tammany's Clock Has Run Down". The New York Times. November 2, 1894.
- Clarence Lexow at Find a Grave
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