[2] Harry Chesler registered for the draft on September 12, 1918, and served as a U.S. Army private during World War I.

[3] By April 1923, he owned the outdoor advertising firm the Harry "A" Chesler Company of 15 Beecher Street in Newark, New Jersey.

[2][6] In 1928, he bought a 90-acre summer-home property in the Succasunna section of Roxbury Township, New Jersey, and opened a side-business dairy store.

[3][7] In 1935[8][9][a] or 1936,[8][10] Chesler established a studio in Manhattan to supply comic-book content to publishers testing the waters of the emerging medium.

[3] George Tuska, a comic-book artist who had worked for Chesler in the late 1930s, recalled, "Chelser had his office on the fourth floor of a building on 23rd Street between Sixth and Seventh Avenue[s]".

[7] Chesler employees remembered him as a tough but warm boss who always wore a hat and smoked a big cigar.

[3] Artist Joe Kubert recalled Chesler paying him $5 a week, at age 12 (c. 1938) to apprentice at his studio after school.

[3] Similarly, artist Carmine Infantino remembers that, c. 1940, he was paid by Chesler "a dollar a day, just [to] study art, learn, and grow.

"[citation needed] In his heyday, Chesler recalled in a 1976 profile, "besides about 75 of my own titles, we produced comics for some 50 different publishers.

[8] Alumni of the Chesler Shop "went on to form the nuclei of various comics art staffs" for a number of different early comics companies;[8] they include Jack Cole,[citation needed] Jack Binder,[20] Otto Binder,[21] Charles Biro,[22] Mort Meskin,[23] Creig Flessel (briefly),[24] Ken Ernst,[25] Bob McCay,[26] Otto Eppers,[27] and many others.

Chesler's main pre-war editor, Phil Sturm, was on active duty for most of the war, severely curtailing the company's ability to produce comics.