Born Jacquin Leonard Lait in New York City, he became renowned during his 50-year career in journalism as one of the leading newspapermen of the first half of the 20th century. He wrote a syndicated column called All in the Family for two decades, and his comic strip, Gus and Gussie, illustrated by Paul Fung, ran from April 13, 1925 to February 24, 1930.
He was the editor of the New York Daily Mirror and Sunday Mirror, and he ended his career working for the Hearst Corporation. During his tenure as editor, the New York Daily Mirror gained the second highest circulation of any U.S. newspaper. In 1963, nine years after Lait's death, it ceased publication following a strike and was absorbed into the then top-selling paper the New York Daily News.
Lait died of a circulatory ailment in Beverly Hills, California at the age of 71.
- Help Wanted, February 11, 1914 - May 1914
- One of Us, September 9, 1918 - Sep 1918
- Spice of 1922, [Original, Musical, Revue] July 6, 1922 - Sep 9, 1922
- Rufus LeMaire's Affairs, [Original, Musical, Revue] March 28, 1927 - May 1927
- The Hook-up, May 7, 1935 - May 1935
- Beef, Iron, and Wine – Garden City, Doubleday, Page & Co 1916
- Put on the Spot – NY: Grosset & Dunlap (1930) (basis of 1931 film Bad Company)
- The Beast of the City; NY Grosset & Dunlap (1932), novelization of the screenplay by W.R. Burnett
- Our Will Rogers – NY, Greenberg 1935
- New York Confidential, The Lowdown on Its Bright Life (with Lee Mortimer) – Chicago: Ziff-Davis, 1948
- Washington Confidential (with Mortimer – Crown Publishers 1951
- Chicago Confidential (with Mortimer) – Crown 1950
- U.S.A. Confidential (with Mortimer) – Crown 1952
- Lait, Jack and Lee Mortimer. Washington Confidential New York: Crown Publishers, 1951.